157 lines
4.6 KiB
C++
157 lines
4.6 KiB
C++
#include <stdio.h>
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#include <string.h>
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#include <math.h>
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#define eps 0.00000001
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double x_0, y_0;
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double a[5], b[5], c[5];
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double ansx[5], ansy[5], ansr[5];
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int flag[5];
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void exchange(double &x, double &y)
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{
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double tmp = x;
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x = y;
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y = tmp;
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return ;
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}
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double dis(double x_1, double y_1, double x_2, double y_2)
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{
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return sqrt((x_1 - x_2) * (x_1 - x_2) + (y_1 - y_2) * (y_1 - y_2));
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}
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void changepoint(double x, double y, double &ex, double &ey)
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{
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double d = dis(x, y, x_0, y_0);
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ey = y_0 + (y - y_0) / (d * d);
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ex = x_0 + (x - x_0) / (d * d);
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return ;
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}
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void changecircle(double x, double y, double r, double &ex, double &ey, double &er)
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{
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double x_1, y_1, x_2, y_2;
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if(fabs(x - x_0) < eps)
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{
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changepoint(x, y + r, x_1, y_1);
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changepoint(x, y- r, x_2, y_2);
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}
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else
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{
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double k = (y - y_0) / (x - x_0);
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double tmp = sqrt(r * r / (1 + k * k));
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changepoint(tmp + x, k * tmp + y, x_1, y_1);
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changepoint(-tmp + x, -k * tmp + y, x_2, y_2);
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}
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ex = (x_1 + x_2) / 2;
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ey = (y_1 + y_2) / 2;
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er = dis(x_1, y_1, x_2, y_2) / 2;
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return ;
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}
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void rotate(double s, double t, double &aa, double &bb, double &cc, double sinct, double cosct)
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{
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double tmpa = aa, tmpb = bb, tmpc = cc;
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aa = tmpa * cosct - tmpb * sinct;
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bb = tmpa * sinct + tmpb * cosct;
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cc = tmpc + tmpa * s * cosct + tmpa * t * sinct - tmpa * s
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- tmpb * s * sinct + tmpb * t * cosct - tmpb * t;
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return ;
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}
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void getline(double x_1, double y_1, double r_1, double x_2, double y_2, double r_2)
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{
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double tmpa, tmpb, tmpc;
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tmpa = y_2 - y_1;
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tmpb = x_1 - x_2;
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tmpc = y_1 * (x_1 - x_2) - x_1 * (y_1 - y_2);
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double d, detr;
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d = dis(x_1, y_1, x_2, y_2);
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detr = r_2 - r_1;
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double sinct = fabs(detr) / d;
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double cosct = sqrt(d * d - detr * detr) / d;
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double aa = tmpa, bb = tmpb, cc = tmpc;
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rotate(x_1, y_1, aa, bb, cc, sinct, cosct);
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a[0] = aa;
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b[0] = bb;
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c[0] = cc - r_1 * sqrt(a[0] * a[0] + b[0] * b[0]);
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aa = tmpa, bb = tmpb, cc = tmpc;
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rotate(x_1, y_1, aa, bb, cc, -sinct, cosct);
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a[1] = aa;
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b[1] = bb;
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c[1] = cc + r_1 * sqrt(a[1] * a[1] + b[1] * b[1]);
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return ;
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}
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void getcircle(double aa, double bb, double cc, int k)
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{
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if(fabs(aa * x_0 + bb * y_0 - cc) < eps)
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{
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flag[k] = 0;
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return ;
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}
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double s, t, ex, ey;
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s = (aa * cc + x_0 * bb * bb - aa * bb * y_0) / (aa * aa + bb * bb);
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t = (bb * cc - x_0 * aa * bb + aa * aa * y_0) / (aa * aa + bb * bb);
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changepoint(s, t, ex, ey);
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ansx[k] = (x_0 + ex) / 2;
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ansy[k] = (y_0 + ey) / 2;
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ansr[k] = dis(x_0, y_0, ex, ey) / 2;
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return ;
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}
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double x_00,y_00,x_11,y_11,x_22,y_22,r_11,r_22;
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bool check(double x, double y, double r)
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{
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if (fabs(dis(x,y,x_00,y_00) - r) < eps)
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if (fabs(dis(x,y,x_11,y_11) - r - r_11) < eps)
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if (fabs(dis(x,y,x_22,y_22) - r - r_22) < eps)
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return true;
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return false;
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}
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double get_dis(double aa, double bb, double cc,double x, double y)
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{
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return fabs((aa*x + bb*y - cc)/sqrt(aa*aa + bb*bb));
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}
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int main()
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{
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int T = 100;
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double x_1, y_1, r_1, x_2, y_2, r_2;
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scanf("%d", &T);
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while(T--)
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{
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scanf("%lf%lf%lf", &x_1, &y_1, &r_1);
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scanf("%lf%lf%lf", &x_2, &y_2, &r_2);
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scanf("%lf%lf", &x_0, &y_0);
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x_00 = x_0;
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y_00 = y_0;
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x_11 = x_1;
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y_11 = y_1;
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x_22 = x_2;
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y_22 = y_2;
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r_11 = r_1;
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r_22 = r_2;
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double ex_1, ex_2, ey_1, ey_2, er_1, er_2;
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changecircle(x_1, y_1, r_1, ex_1, ey_1, er_1);
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changecircle(x_2, y_2, r_2, ex_2, ey_2, er_2);
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if(er_1 > er_2)
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{
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exchange(ex_1, ex_2);
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exchange(ey_1, ey_2);
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exchange(er_1, er_2);
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}
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getline(ex_1, ey_1, er_1, ex_2, ey_2, er_2);
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memset(flag, -1, sizeof(flag));
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getcircle(a[0], b[0], c[0], 0);
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getcircle(a[1], b[1], c[1], 1);
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int ans = 0;
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for (int i=0; i < 2;i++)
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{
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if (check(ansx[i],ansy[i],ansr[i])){
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ans++;
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flag[i] = 1;
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}
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}
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printf("%d\n", ans);
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for(int i = 0; i < 2; i++)
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{
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if(flag[i] == 1){
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printf("%.8lf %.8lf %.8lf\n", ansx[i], ansy[i], ansr[i]);
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}
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}
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}
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return 0;
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}
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