826 lines
22 KiB
Plaintext
826 lines
22 KiB
Plaintext
===============数学方面模板===========
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计算几何模板，包含：
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\begin{itemize}
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\item point2/3 点/向量，方法：向量加+减-，数乘*，点乘*，叉乘%，模dis，辐角arg（2维），旋转rotate（2维），平行parallel，垂直perpend，三维点根据所在面的法向量和一个面上向量投影为二维点以及反投影
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\item line2/3 线，表示为起点+方向向量，方法：点线距和垂足，线线交、线段线段交（线段交可退化，2维），线线距和最近点对（3维，若平行返回任意一对），线的投影（同点）
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\item face3 面，表示为起点+法向量，方法：点面距和垂足，线面交，面面交
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\item circle2 圆，表示为圆心+半径，方法：线圆交，圆圆交，点到圆的切点，圆与圆的公切线（若公切线有两个切点，返回直线两端点为两切点，否则返回直线端点为切点）
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\item convex2 凸包，方法：面积，点不严格在凸包内，线与凸包交，水平序Graham求凸包，半平面交（半平面为传入向量左侧平面）
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\end{itemize}
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说明：对需要求点/线的，点/线作为指针传入，若为NULL表示不需要（默认）；对需要求点/线个数的，返回值为-1表示有无穷多个。
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#include <cstdio>
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#include <cmath>
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#include <vector>
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#include <deque>
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#include <algorithm>
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const double eps = 1e-13;
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const double pi = 3.14159265358979324;
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struct point2
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{
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double x, y;
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point2& operator += (point2 a)
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{
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x+=a.x, y+=a.y;
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return *this;
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}
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point2& operator -= (point2 a)
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{
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x-=a.x, y-=a.y;
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return *this;
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}
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point2& operator *= (double a)
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{
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x*=a, y*=a;
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return *this;
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}
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point2& operator /= (double a)
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{
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x/=a, y/=a;
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return *this;
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}
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};
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point2 operator + (point2 a, point2 b)
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{
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point2 c(a);
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c += b;
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return c;
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}
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point2 operator - (point2 a, point2 b)
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{
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point2 c(a);
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c -= b;
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return c;
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}
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point2 operator * (point2 a, double b)
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{
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point2 c(a);
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c *= b;
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return c;
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}
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point2 operator * (double a, point2 b)
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{
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point2 c(b);
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c *= a;
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return c;
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}
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point2 operator / (point2 a, double b)
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{
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point2 c(a);
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c /= b;
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return c;
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}
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double operator * (point2 a, point2 b)
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{
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return a.x*b.x+a.y*b.y;
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}
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double operator % (point2 a, point2 b)
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{
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return a.x*b.y-a.y*b.x;
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}
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double dis(point2 a)
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{
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return sqrt(a.x * a.x + a.y * a.y);
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}
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double arg(point2 a)
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{
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return atan2(a.y, a.x);
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}
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point2 rotate(point2 a, double th)
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{
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point2 b;
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b.x = a.x * cos(th) - a.y * sin(th);
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b.y = a.x * sin(th) + a.y * cos(th);
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return b;
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}
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int parallel(point2 a, point2 b)
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{
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return a * a < eps * eps || b * b < eps * eps
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|| (a % b) * (a % b) / ((a * a) * (b * b)) < eps * eps;
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}
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int perpend(point2 a, point2 b)
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{
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return a * a < eps * eps || b * b < eps * eps
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|| (a * b) * (a * b) / ((a * a) * (b * b)) < eps * eps;
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}
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struct line2
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{
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point2 a, s;
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};
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struct circle2
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{
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point2 a;
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double r;
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};
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double point_line_dis(point2 a, line2 b, point2 *res = NULL)
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{
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point2 p;
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p = b.a + ((a - b.a) * b.s) / (b.s * b.s) * b.s;
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if (res != NULL) *res = p;
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return dis(a - p);
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}
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int line_line_cross(line2 a, line2 b, point2 *res = NULL)
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{
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if (parallel(a.s, b.s))
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if (parallel(b.a - a.a, a.s))
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return -1;
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else
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return 0;
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double k1 = (b.a - a.a) % b.s / (a.s % b.s);
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if (res != NULL) *res = a.a + k1 * a.s;
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return 1;
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}
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int segment_segment_cross(line2 a, line2 b, point2 *res = NULL)
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{
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if (a.s * a.s < eps * eps && b.s * b.s < eps * eps)
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if ((b.a - a.a) * (b.a - a.a) < eps * eps)
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{
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if (res != NULL) *res = a.a;
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return 1;
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}
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else
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return 0;
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if (parallel(a.s, b.s) && parallel(b.a - a.a, a.s) && parallel(a.a - b.a, b.s))
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{
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double y1, y2, y3, y4;
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point2 y1p = a.a, y2p = a.a + a.s, y3p = b.a, y4p = b.a + b.s;
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if (std::abs(a.s.x) < std::abs(a.s.y) || std::abs(b.s.x) < std::abs(b.s.y))
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y1 = y1p.y, y2 = y2p.y, y3 = y3p.y, y4 = y4p.y;
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else
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y1 = y1p.x, y2 = y2p.x, y3 = y3p.x, y4 = y4p.x;
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if (y1 > y2) std::swap(y1, y2), std::swap(y1p, y2p);
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if (y3 > y4) std::swap(y3, y4), std::swap(y3p, y4p);
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if (y2 - y1 < y4 - y3) std::swap(y1, y3), std::swap(y1p, y3p), std::swap(y2, y4), std::swap(y2p, y4p);
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if (y3 > y2 + (y2 - y1) * eps || y4 < y1 - (y2 - y1) * eps)
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return 0;
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else if (fabs(y3 - y2) < (y2 - y1) * eps || fabs(y3 - y4) < eps)
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{
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if (res != NULL) *res = y3p;
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return 1;
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}
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else if (fabs(y4 - y1) < (y2 - y1) * eps || fabs(y1 - y2) < eps)
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{
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if (res != NULL) *res = y1p;
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return 1;
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}
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else
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return -1;
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}
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else
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{
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double k1 = (b.a - a.a) % a.s, k2 = (b.a + b.s - a.a) % a.s;
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k1 /= a.s * a.s, k2 /= a.s * a.s;
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double k3 = (a.a - b.a) % b.s, k4 = (a.a + a.s - b.a) % b.s;
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k3 /= b.s * b.s, k4 /= b.s * b.s;
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int ret = (k1 < eps && k2 > -eps || k1 > -eps && k2 < eps)
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&& (k3 < eps && k4 > -eps || k3 > -eps && k4 < eps);
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if (ret) line_line_cross(a, b, res);
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return ret;
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}
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}
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int line_circle_cross(line2 a, circle2 b, point2 *res1 = NULL, point2 *res2 = NULL)
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{
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point2 p;
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double d = point_line_dis(b.a, a, &p);
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if (d / b.r > 1 + eps)
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return 0;
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else if (d / b.r > 1 - eps)
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{
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if (res1 != NULL) *res1 = p;
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return 1;
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}
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else
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{
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d = sqrt(b.r * b.r - d * d) / dis(a.s);
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if (res1 != NULL) *res1 = p + d * a.s;
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if (res2 != NULL) *res2 = p - d * a.s;
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return 2;
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}
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}
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int circle_circle_cross(circle2 a, circle2 b, point2 *res1 = NULL, point2 *res2 = NULL)
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{
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double d = dis(a.a - b.a);
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point2 u = (b.a - a.a) / d;
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if (d / (a.r + b.r) > 1 + eps)
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return 0;
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else if (d / (a.r + b.r) > 1 - eps)
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{
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if (res1 != NULL) *res1 = a.a + u * a.r;
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return 1;
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}
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else if ((d - fabs(a.r - b.r)) / (a.r + b.r) > eps)
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{
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double th = acos((a.r * a.r + d * d - b.r * b.r) / (2 * a.r * d));
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if (res1 != NULL) *res1 = a.a + rotate(u * a.r, th);
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if (res2 != NULL) *res2 = a.a + rotate(u * a.r, -th);
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return 2;
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}
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else if ((d - fabs(a.r - b.r)) / (a.r + b.r) > -eps)
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{
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if (a.r / b.r < 1 - eps)
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{
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if (res1 != NULL) *res1 = b.a - u * b.r;
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return 1;
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}
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else if (a.r / b.r > 1 + eps)
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{
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if (res1 != NULL) *res1 = a.a + u * a.r;
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return 1;
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}
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else return -1;
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}
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else
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return 0;
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}
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int point_circle_tangent(point2 a, circle2 b, point2 *res1 = NULL, point2 *res2 = NULL)
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{
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double d = dis(a - b.a);
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point2 u = (a - b.a) / d;
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if (d / b.r > 1 + eps)
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{
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double th = acos(b.r / d);
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if (res1 != NULL) *res1 = b.a + rotate(u * b.r, th);
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if (res2 != NULL) *res2 = b.a + rotate(u * b.r, -th);
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return 2;
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}
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else if (d / b.r > 1 - eps)
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{
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if (res1 != NULL) *res1 = a;
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return 1;
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}
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else
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return 0;
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}
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int circle_circle_tangent(circle2 a, circle2 b, line2 *reso1 = NULL, line2 *reso2 = NULL, line2 *resi1 = NULL, line2 *resi2 = NULL)
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{
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double d = dis(a.a - b.a);
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point2 u = (b.a - a.a) / d;
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int cnt = 0;
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if ((d - fabs(a.r - b.r)) / (a.r + b.r) > eps)
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{
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double th = acos((a.r - b.r) / d);
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if (reso1 != NULL)
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{
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reso1->a = a.a + rotate(u * a.r, th);
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reso1->s = b.a + rotate(u * b.r, th) - reso1->a;
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}
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if (reso2 != NULL)
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{
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reso2->a = a.a + rotate(u * a.r, -th);
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reso2->s = b.a + rotate(u * b.r, -th) - reso2->a;
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}
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cnt += 2;
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}
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else if ((d - fabs(a.r - b.r)) / (a.r + b.r) > -eps)
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{
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if (a.r / b.r < 1 - eps)
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{
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if (reso1 != NULL)
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{
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reso1->a = b.a - u * b.r;
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reso1->s = rotate(u, pi / 2);
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}
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cnt++;
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}
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else if (a.r / b.r > 1 + eps)
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{
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if (reso1 != NULL)
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{
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reso1->a = a.a + u * a.r;
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reso1->s = rotate(u, pi / 2);
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}
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cnt++;
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}
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else return -1;
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}
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if (d / (a.r + b.r) > 1 + eps)
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{
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double th = acos((a.r + b.r) / d);
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if (resi1 != NULL)
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{
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resi1->a = a.a + rotate(u * a.r, th);
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resi1->s = b.a - rotate(u * b.r, th) - resi1->a;
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}
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if (resi2 != NULL)
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{
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resi2->a = a.a + rotate(u * a.r, -th);
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resi2->s = b.a - rotate(u * b.r, -th) - resi2->a;
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}
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cnt += 2;
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}
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else if (d / (a.r + b.r) > 1 - eps)
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{
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if (resi1 != NULL)
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{
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resi1->a = a.a + u * a.r;
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resi1->s = rotate(u, pi / 2);
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}
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cnt++;
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}
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return cnt;
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}
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typedef std::vector<point2> convex2;
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double area(const convex2 &a)
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{
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double s = 0;
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for (int i = 0; i < a.size(); i++)
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s += a[i] % a[(i+1)%a.size()];
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return fabs(s)/2;
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}
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int point_convex_inside(point2 a, const convex2 &b)
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{
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double sum = 0;
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for (int i = 0; i < b.size(); i++)
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sum += fabs((b[i] - a) % (b[(i+1)%b.size()] - a));
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return fabs(sum / (2*area(b)) - 1) < eps;
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}
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int line_convex_cross(line2 a, const convex2 &b, point2 *res1 = NULL, point2 *res2 = NULL)
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{
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int cnt = 0;
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for (int i = 0; i < b.size(); i++)
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{
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line2 ltmp;
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point2 ptmp;
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ltmp.a = b[i], ltmp.s = b[(i+1)%b.size()] - b[i];
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int flag = line_line_cross(a, ltmp, &ptmp);
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if (flag == -1) return -1;
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if (flag == 0) continue;
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double k = (ptmp - ltmp.a) * ltmp.s / (ltmp.s * ltmp.s);
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if (k < eps || k > 1+eps) continue;
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if (cnt == 0 && res1 != NULL) *res1 = ptmp;
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else if (cnt == 1 && res2 != NULL) *res2 = ptmp;
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cnt++;
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}
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return cnt;
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}
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int convex_gen_cmp(point2 a, point2 b)
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{
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return a.y < b.y - eps || fabs(a.y - b.y) < eps && a.x < b.x - eps;
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}
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int convex_gen(const convex2 &a, convex2 &b)
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{
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std::deque<point2> q;
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convex2 t(a);
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std::sort(t.begin(), t.end(), convex_gen_cmp);
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q.push_back(t[0]), q.push_back(t[1]);
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for (int i = 2; i < t.size(); i++)
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{
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while (q.size() > 1)
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{
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point2 p1 = t[i]-q[q.size()-1], p2 = q[q.size()-1]-q[q.size()-2];
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if (p1 % p2 > 0 || parallel(p1, p2)) q.pop_back();
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else break;
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}
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q.push_back(t[i]);
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}
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int pretop = q.size();
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for (int i = t.size()-1; i >= 0; i--)
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{
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while (q.size() > pretop)
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{
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point2 p1 = t[i]-q[q.size()-1], p2 = q[q.size()-1]-q[q.size()-2];
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if (p1 % p2 > 0 || parallel(p1, p2)) q.pop_back();
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else break;
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}
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q.push_back(t[i]);
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}
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q.pop_back();
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if (q.size() < 3)
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{
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b.clear();
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return 0;
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}
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b.clear();
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for (int i = 0; i < q.size(); i++) b.push_back(q[i]);
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return 1;
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}
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int halfplane_cross_cmp(line2 a, line2 b)
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{
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double c1 = arg(a.s), c2 = arg(b.s);
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return c1 < c2-eps || fabs(c1-c2) < eps && b.s % (a.a - b.a) / dis(b.s) > eps;
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}
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int halfplane_cross(const std::vector<line2> &a, convex2 &b)
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{
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std::vector<line2> t(a);
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std::sort(t.begin(), t.end(), halfplane_cross_cmp);
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int j = 0;
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for (int i = 0; i < t.size(); i++)
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if (!i || arg(t[i].s) > arg(t[i-1].s) + eps) t[j++] = t[i];
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if (j > 0 && arg(t[j].s) > arg(t[0].s) + 2*pi - eps) j--;
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t.resize(j);
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std::deque<line2> q;
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q.push_back(t[0]), q.push_back(t[1]);
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point2 p;
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for (int i = 2, k = 0; i < t.size(); i++)
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{
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for (; k < q.size() && t[i].s % q[k].s > 0; k++);
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point2 s1 = q[q.size()-1].s, s2 = q[0].s;
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if (k > 0 && k < q.size() && s1 % s2 > 0 && !parallel(s1, s2))
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{
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line_line_cross(q[k], q[k-1], &p);
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double r1 = t[i].s % (p - t[i].a) / dis(t[i].s);
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line_line_cross(q[0], q[q.size()-1], &p);
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double r2 = t[i].s % (p - t[i].a) / dis(t[i].s);
|
||
if (r1 < eps && r2 < eps)
|
||
{
|
||
b.clear();
|
||
return 0;
|
||
}
|
||
else if (r1 > -eps && r2 > -eps)
|
||
continue;
|
||
}
|
||
while (q.size() > 1)
|
||
{
|
||
line_line_cross(q[q.size()-1], q[q.size()-2], &p);
|
||
if (t[i].s % (p - t[i].a) / dis(t[i].s) < eps)
|
||
{
|
||
q.pop_back();
|
||
if (k == q.size()) k--;
|
||
}
|
||
else break;
|
||
}
|
||
while (q.size() > 1)
|
||
{
|
||
line_line_cross(q[0], q[1], &p);
|
||
if (t[i].s % (p - t[i].a) / dis(t[i].s) < eps)
|
||
{
|
||
q.pop_front();
|
||
k--;
|
||
if (k < 0) k = 0;
|
||
}
|
||
else break;
|
||
}
|
||
q.push_back(t[i]);
|
||
}
|
||
b.clear();
|
||
for (int i = 0; i < q.size(); i++)
|
||
{
|
||
line_line_cross(q[i], q[(i+1)%q.size()], &p);
|
||
b.push_back(p);
|
||
}
|
||
return 1;
|
||
}
|
||
struct point3
|
||
{
|
||
double x, y, z;
|
||
point3& operator += (point3 a)
|
||
{
|
||
x+=a.x,y+=a.y,z+=a.z;
|
||
return *this;
|
||
}
|
||
point3& operator -= (point3 a)
|
||
{
|
||
x-=a.x,y-=a.y,z-=a.z;
|
||
return *this;
|
||
}
|
||
point3& operator *= (double a)
|
||
{
|
||
x*=a, y*=a, z*=a;
|
||
return *this;
|
||
}
|
||
point3& operator /= (double a)
|
||
{
|
||
x/=a, y/=a, z/=a;
|
||
return *this;
|
||
}
|
||
};
|
||
point3 operator + (point3 a, point3 b)
|
||
{
|
||
point3 c(a);
|
||
c += b;
|
||
return c;
|
||
}
|
||
point3 operator - (point3 a, point3 b)
|
||
{
|
||
point3 c(a);
|
||
c -= b;
|
||
return c;
|
||
}
|
||
point3 operator * (point3 a, double b)
|
||
{
|
||
point3 c(a);
|
||
c *= b;
|
||
return c;
|
||
}
|
||
point3 operator * (double a, point3 b)
|
||
{
|
||
point3 c(b);
|
||
c *= a;
|
||
return c;
|
||
}
|
||
point3 operator / (point3 a, double b)
|
||
{
|
||
point3 c(a);
|
||
c /= b;
|
||
return c;
|
||
}
|
||
double operator * (point3 a, point3 b)
|
||
{
|
||
return a.x*b.x+a.y*b.y+a.z*b.z;
|
||
}
|
||
point3 operator % (point3 a, point3 b)
|
||
{
|
||
point3 c;
|
||
c.x = a.y * b.z - a.z * b.y;
|
||
c.y = a.z * b.x - a.x * b.z;
|
||
c.z = a.x * b.y - a.y * b.x;
|
||
return c;
|
||
}
|
||
double dis(point3 a)
|
||
{
|
||
return sqrt(a.x * a.x + a.y * a.y + a.z * a.z);
|
||
}
|
||
int parallel(point3 a, point3 b)
|
||
{
|
||
return a * a < eps * eps || b * b < eps * eps
|
||
|| (a % b) * (a % b) / ((a * a) * (b * b)) < eps * eps;
|
||
}
|
||
int perpend(point3 a, point3 b)
|
||
{
|
||
return a * a < eps * eps || b * b < eps * eps
|
||
|| (a * b) * (a * b) / ((a * a) * (b * b)) < eps * eps;
|
||
}
|
||
struct line3
|
||
{
|
||
point3 a, s;
|
||
};
|
||
struct face3
|
||
{
|
||
point3 a, n;
|
||
};
|
||
struct circle3
|
||
{
|
||
point3 a;
|
||
double r;
|
||
};
|
||
point2 project(point3 a, face3 b, point3 xs)
|
||
{
|
||
point3 ys;
|
||
ys = b.n % xs;
|
||
point2 c;
|
||
c.x = ((a - b.a) * xs) / dis(xs), c.y = ((a - b.a) * ys) / dis(ys);
|
||
return c;
|
||
}
|
||
line2 project(line3 a, face3 b, point3 xs)
|
||
{
|
||
line2 c;
|
||
c.a = project(a.a, b, xs), c.s = project(a.a + a.s, b, xs) - c.a;
|
||
return c;
|
||
}
|
||
point3 revproject(point2 a, face3 b, point3 xs)
|
||
{
|
||
point3 ys;
|
||
ys = b.n % xs;
|
||
return a.x * xs / dis(xs) + a.y * ys / dis(ys) + b.a;
|
||
}
|
||
line3 revproject(line2 a, face3 b, point3 xs)
|
||
{
|
||
line3 c;
|
||
c.a = revproject(a.a, b, xs), c.s = revproject(a.a + a.s, b, xs) - c.a;
|
||
return c;
|
||
}
|
||
double point_line_dis(point3 a, line3 b, point3 *res = NULL)
|
||
{
|
||
point3 p;
|
||
p = b.a + ((a - b.a) * b.s) / (b.s * b.s) * b.s;
|
||
if (res != NULL) *res = p;
|
||
return dis(a - p);
|
||
}
|
||
double point_face_dis(point3 a, face3 b, point3 *res = NULL)
|
||
{
|
||
point3 p;
|
||
p = ((a - b.a) * b.n) / (b.n * b.n) * b.n;
|
||
if (res != NULL) *res = a - p;
|
||
return dis(p);
|
||
}
|
||
double line_line_dis(line3 a, line3 b, point3 *resa = NULL, point3 *resb = NULL)
|
||
{
|
||
point3 p;
|
||
if (parallel(a.s, b.s))
|
||
{
|
||
double d = point_line_dis(a.a, b, &p);
|
||
if (resa != NULL) *resa = a.a;
|
||
if (resb != NULL) *resb = p;
|
||
return d;
|
||
}
|
||
point3 n = a.s % b.s;
|
||
face3 f;
|
||
f.a = b.a, f.n = n;
|
||
double d = point_face_dis(a.a, f, &p);
|
||
double k1 = ((b.a - p) % b.s) * n / (n * n);
|
||
if (resb != NULL) *resb = p + k1 * a.s;
|
||
if (resa != NULL) *resa = a.a + k1 * a.s;
|
||
return d;
|
||
}
|
||
int line_face_cross(line3 a, face3 b, point3 *res = NULL)
|
||
{
|
||
if (perpend(a.s, b.n))
|
||
if (perpend(b.a - a.a, b.n))
|
||
return -1;
|
||
else
|
||
return 0;
|
||
double k = (b.a - a.a) * b.n / (a.s * b.n);
|
||
if (res != NULL) *res = a.a + k * a.s;
|
||
return 1;
|
||
}
|
||
int face_face_cross(face3 a, face3 b, line3 *res = NULL)
|
||
{
|
||
if (parallel(a.n, b.n))
|
||
if (perpend(b.a - a.a, a.n))
|
||
return -1;
|
||
else
|
||
return 0;
|
||
point3 s = a.n % b.n;
|
||
point3 p;
|
||
line3 t;
|
||
t.a = a.a, t.s = a.n % s;
|
||
line_face_cross(t, b, &p);
|
||
if (res != NULL)
|
||
res->a = p, res->s = s;
|
||
return 1;
|
||
}
|
||
|
||
=============数论模板==========
|
||
数论模板，其中包含：
|
||
\begin{itemize}
|
||
\item ext\_gcd：扩展欧几里得方法解 $ax+by=\gcd(a,b)$，该函数保证当 $a,b>0$ 时 $x>0$。
|
||
\item flsum：欧几里得思想解 $\sum_{x=st}^{ed}\lfloor\frac{ax+b}c\rfloor$。
|
||
\item ind：小步大步走算法求 $a^x=m\pmod b$。
|
||
\item prepare\_inv：$O(p)$ 求模 $p$ 域下所有非零元的逆元（$p$ 素数）。
|
||
\end{itemize}
|
||
|
||
#include <cstdlib>
|
||
#include <cmath>
|
||
#include <map>
|
||
#include <vector>
|
||
#include <algorithm>
|
||
void ext_gcd(int a, int b, int &x, int &y)
|
||
{
|
||
if (!b) x = 1, y = 0;
|
||
else if (!a) x = 1, y = -1;
|
||
else if (a > b) ext_gcd(a % b, b, x, y), y += a / b * x;
|
||
else ext_gcd(a, b % a, x, y), x += b / a * y;
|
||
}
|
||
long long flsum_t (long long a, long long b, long long c, long long n)
|
||
{
|
||
if (n < 0) return 0;
|
||
if (c < 0) a = -a, b = -b, c = -c;
|
||
n++;
|
||
long long res = 0;
|
||
if (a < 0 || a >= c)
|
||
{
|
||
long long ra = (a % c + c) % c;
|
||
long long k = (a - ra) / c;
|
||
res += k * n * (n - 1) / 2;
|
||
a = ra;
|
||
}
|
||
if (b < 0 || b >= c)
|
||
{
|
||
long long rb = (b % c + c) % c;
|
||
long long k = (b - rb) / c;
|
||
res += k * n;
|
||
b = rb;
|
||
}
|
||
if (a * n + b < c) return res;
|
||
else return res + flsum_t(c, (a * n + b) % c, a, (a * n + b) / c - 1);
|
||
}
|
||
long long flsum (long long a, long long b, long long c, long long st, long long ed)
|
||
{
|
||
return flsum_t(a, b, c, ed) - flsum_t(a, b, c, st - 1);
|
||
}
|
||
int power(int n, int k, int r)
|
||
{
|
||
int t = n, s = 1;
|
||
for (; k; k >>= 1, t = 1LL * t * t % r)
|
||
if (k & 1) s = 1LL * s * t % r;
|
||
return s;
|
||
}
|
||
int millerrabin(int x, int tester)
|
||
{
|
||
int k = x-1;
|
||
for (; !(k & 1); k >>= 1);
|
||
int y = power(tester, k, x);
|
||
if (y == 1) return 1;
|
||
for (; k < x-1; k <<= 1, y = 1LL * y * y % x)
|
||
if (y == x-1) return 1;
|
||
return 0;
|
||
}
|
||
int isprime(int x)
|
||
{
|
||
if (x == 2 || x == 7 || x == 61) return 1;
|
||
return millerrabin(x, 2) && millerrabin(x, 7) && millerrabin(x, 61);
|
||
}
|
||
int rho_f(int x, int c, int p)
|
||
{
|
||
return (1LL * x * x + c) % p;
|
||
}
|
||
int rho(int n)
|
||
{
|
||
int c = rand() % (n-1) + 1, x = 2, y = x, d = 1;
|
||
while (d == 1)
|
||
{
|
||
x = rho_f(x, c, n);
|
||
y = rho_f(rho_f(y, c, n), c, n);
|
||
d = std::__gcd(y > x ? y-x : x-y, n);
|
||
}
|
||
return d;
|
||
}
|
||
void factor(int n, std::vector<int> &res)
|
||
{
|
||
if (n == 1) return;
|
||
else if (isprime(n)) res.push_back(n);
|
||
else if (n == 4) res.push_back(2), res.push_back(2);
|
||
else
|
||
{
|
||
int d;
|
||
while ((d = rho(n)) == n);
|
||
factor(d, res), factor(n / d, res);
|
||
}
|
||
}
|
||
int ind(int a, int b, int m)
|
||
{
|
||
a %= m, b %= m;
|
||
std::map<int, int> hash;
|
||
int r = (int)(sqrt(m)), k = 1;
|
||
if (r * r < m) r++;
|
||
for (int i = 0; i < r; i++, k = 1LL * k * a % m)
|
||
if (hash.find(k) == hash.end())
|
||
hash.insert(std::make_pair(k, i));
|
||
int s = 1;
|
||
std::map<int, int>::iterator it;
|
||
for (int i = 0; i < r; i++, s = 1LL * s * k % m)
|
||
{
|
||
int x, y, t;
|
||
ext_gcd(s, m, x, y);
|
||
t = 1LL * b * x % m;
|
||
if ((it = hash.find(t)) != hash.end())
|
||
return i * r + it->second;
|
||
}
|
||
}
|
||
void prepare_inv(int *inv, int p)
|
||
{
|
||
inv[1] = 1;
|
||
for (int i = 2; i < p; i++)
|
||
inv[i] = 1LL * inv[p%i] * (p - p/i) % p;
|
||
}
|
||
|
||
|
||
=================数值计算=============
|
||
数值计算模板，内含：
|
||
\begin{itemize}
|
||
\item area\_simpson：Simpson法求定积分。
|
||
\item fft\_prepare：求 $maxn$ 次单位根，包括负指数。
|
||
\item dft：做长度为 $N(N|maxn)$ 的DFT，其中若 $f=-1$ 则求IDFT。
|
||
\end{itemize}
|
||
|
||
#include <cmath>
|
||
#include <algorithm>
|
||
#include <complex>
|
||
const double pi = 3.14159265358979324;
|
||
typedef double (*__F) (double);
|
||
double area(double x, double y, double fl, double fmid, double fr)
|
||
{
|
||
return (fl + 4 * fmid + fr) * (y - x) / 6;
|
||
}
|
||
double area_simpson_solve(__F f, double x, double mid, double y, double fl, double fmid, double fr, double pre, double zero)
|
||
{
|
||
double lmid = (x + mid) / 2, rmid = (mid + y) / 2;
|
||
double flmid = f(lmid), frmid = f(rmid);
|
||
double al = area(x, mid, fl, flmid, fmid), ar = area(mid, y, fmid, frmid, fr);
|
||
if (fabs(al + ar - pre) < zero) return al + ar;
|
||
else return area_simpson_solve(f, x, lmid, mid, fl, flmid, fmid, al, zero) + area_simpson_solve(f, mid, rmid, y, fmid, frmid, fr, ar, zero);
|
||
}
|
||
double area_simpson(__F f, double x, double y, double zero = 1e-10)
|
||
{
|
||
double mid = (x + y) / 2, fl = f(x), fmid = f(mid), fr = f(y);
|
||
return area_simpson_solve(f, x, mid, y, fl, fmid, fr, area(x, y, fl, fmid, fr), zero);
|
||
}
|
||
typedef std::complex<double> complex;
|
||
void fft_prepare(int maxn, complex *&e)
|
||
{
|
||
e = new complex[2 * maxn - 1];
|
||
e += maxn - 1;
|
||
e[0] = complex(1, 0);
|
||
for (int i = 1; i < maxn; i <<= 1)
|
||
e[i] = complex(cos(2 * pi * i / maxn), sin(2 * pi * i / maxn));
|
||
for (int i = 3; i < maxn; i++)
|
||
if ((i & -i) != i) e[i] = e[i - (i & -i)] * e[i & -i];
|
||
for (int i = 1; i < maxn; i++) e[-i] = e[maxn - i];
|
||
}
|
||
/* f = 1: dft; f = -1: idft */
|
||
void dft(complex *a, int N, int f, complex *e, int maxn)
|
||
{
|
||
int d = maxn / N * f;
|
||
complex x;
|
||
for (int n = N, m; m = n / 2, m >= 1; n = m, d *= 2)
|
||
for (int i = 0; i < m; i++)
|
||
for (int j = i; j < N; j += n)
|
||
x = a[j] - a[j+m], a[j] += a[j+m], a[j+m] = x * e[d * i];
|
||
for (int i = 0, j = 1; j < N - 1; j++)
|
||
{
|
||
for (int k = N / 2; k > (i ^= k); k /= 2);
|
||
if (j < i) std::swap(a[i], a[j]);
|
||
}
|
||
}
|