108 lines
2.3 KiB
C++
108 lines
2.3 KiB
C++
#include<stdio.h>
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#include<string.h>
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#include<stdlib.h>
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#include<algorithm>
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using namespace std;
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const int MAXN = 20;
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const int MAXM = 820;
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int ans, n, d[MAXN][MAXN], m, ns;
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int used[210][210];
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struct point
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{
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int x, y;
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}p[MAXN];
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struct triangle
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{
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int a, b, c;
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}t[MAXM];
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int dist(point p1, point p2)
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{
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int x, y;
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x = p1.x - p2.x;
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y = p1.y - p2.y;
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return x * x + y * y;
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}
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bool ponls(point p0, point p1, point p2)
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{
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int x1, x2, y1, y2;
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x1 = p0.x - p2.x;
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y1 = p0.y - p2.y;
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x2 = p1.x - p2.x;
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y2 = p1.y - p2.y;
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if(x1 * y2 == x2 * y1)
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return true;
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return false;
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}
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bool similar(triangle t1, triangle t2)
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{
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int a1, a2, b1, b2, c1, c2;
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a1 = t1.a, b1 = t1.b, c1 = t1.c;
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a2 = t2.a, b2 = t2.b, c2 = t2.c;
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if(a1 * b2 == b1 * a2 && a1 * c2 == c1 * a2 && b1 * c2 == c1 * b2)
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return true;
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return false;
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}
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void ReadGraph()
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{
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int i, j, k, s, v;
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n = 0;
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memset(used, 0, sizeof used);
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for(i = 1; i <= ns; i ++)
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{
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scanf("%d%d", &s, &v);
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s += 100, v += 100;
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if(used[s][v]) continue;
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used[s][v] = 1;
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p[++ n].x = s;
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p[n]. y = v;
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}
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for(i = 1; i <= n; i ++)
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for(j = 1; j <= n; j ++)
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d[i][j] = d[j][i] = dist(p[i], p[j]);
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}
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void MakeTriangle()
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{
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int i, j, k, temp[3];
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m = 0;
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for(i = 1; i <= n; i ++)
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for(j = i + 1; j <= n; j ++)
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for(k = j + 1; k <= n; k ++)
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{
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if(ponls(p[i], p[j], p[k]))
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continue;
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temp[0] = d[i][j];
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temp[1] = d[j][k];
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temp[2] = d[i][k];
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sort(temp, temp + 3);
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t[++ m].a = temp[0];
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t[m].b = temp[1];
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t[m].c = temp[2];
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}
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}
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void cal()
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{
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int cnt, i, j;
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ans = 0;
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for(i = 1; i <= m; i ++)
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{
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cnt = 1;
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for(j = i + 1; j <= m; j ++)
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{
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if( similar(t[i], t[j]))
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++ cnt;
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}
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ans = max(ans, cnt);
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}
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}
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int main()
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{
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while(scanf("%d", &ns), ns)
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{
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ReadGraph();
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MakeTriangle();
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cal();
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printf("%d\n", ans);
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}
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return 0;
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}
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