109 lines
1.7 KiB
C++
109 lines
1.7 KiB
C++
#include <iostream>
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#include <cstdio>
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#include <cmath>
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#include <cstring>
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using namespace std;
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const double inf = 1e100, EPS = 1e-8;
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const int N = 101;
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double l, now;
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int n,t;
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struct edge
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{
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double x[2], y[2];
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} e[N];
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// WA double 判断正负要用
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int sign(double d)
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{
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if (fabs(d) < EPS)
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{
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return 0;
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}
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else
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return d > 0 ? 1 : -1;
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}
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double cross(double x1, double y1, double x2, double y2)
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{
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return x1 * y2 - x2 * y1;
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}
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int same(double x0, double y0, double x3, double y3, double x1, double y1, double x2, double y2)
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{
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double x = x3 - x0, y = y3 - y0; // y0->x0
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//WA？ 没有用浮点数的大小比较方法
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return sign(cross(x, y, x1 - x0, y1 - y0)) * sign(cross(x, y, x2 - x0, y2 - y0));
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}
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//与所有边比是否相交
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bool ob(int x0, int y0, int x1, int y1)
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{
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for (int i = 1; i <= n; i++)
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{
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if (sign(same(x0,y0,x1,y1,e[i].x[0],e[i].y[0],e[i].x[1],e[i].y[1])) > 0)
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{
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return 0;
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}
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}
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return 1;
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}
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//另一线段的点，连点成线
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bool dot2(int ii, int jj)
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{
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for (int i = 1; i <= n; i++)
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{
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if (i == ii)
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continue;
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for (int j = 0; j < 2; j++)
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{
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if(sign(e[ii].x[jj]-e[i].x[j])==0&&sign(e[ii].y[jj]-e[i].y[j])==0) continue;
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if (ob(e[ii].x[jj], e[ii].y[jj], e[i].x[j], e[i].y[j]))
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{
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return 1;
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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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//找一个点
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bool adot()
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{
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for (int i = 1; i <= n; i++)
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{
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for (int j = 0; j < 2; j++)
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{
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if (dot2(i, j))
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{
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return 1;
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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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int main()
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{
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scanf("%d", &t);
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while (t--)
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{
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scanf("%d", &n);
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memset(&e, 0, sizeof(edge) * (n + 1));
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for (int i = 1; i <= n; i++)
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{
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for (int j = 0; j < 2; j++) // 又是j
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{
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scanf("%lf%lf", &e[i].x[j], &e[i].y[j]);//少一个%lf
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}
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}
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if(n==1)
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{
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printf("Yes!\n");
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continue;
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}
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if(adot())
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{
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printf("Yes!\n");
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}
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else
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{
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printf("No!\n");
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}
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}
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return 0;
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}
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