HDU 1756 Cupid's Arrow(点在多边形内判定)

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No

#include<iostream>
#include<cstdio>
using namespace std;
double a[101],b[101];
int pnpoly(int nvert, double *vertx, double *verty, double testx, double testy)///nvert顶点数，vertx顶点x坐标数组，verty顶点y坐标数组,testx,testy判断坐标
{
    int i, j, c = 0;
    for (i = 0, j = nvert-1; i < nvert; j = i++)
    {
        if ( ((verty[i]>testy) != (verty[j]>testy)) &&(testx < (vertx[j]-vertx[i]) * (testy-verty[i]) / (verty[j]-verty[i]) + vertx[i]) )
            c = !c;
    }
    return c;
}

int main()
{
    int n;
    double p1,p2;
    while (scanf("%d", &n) != EOF)
    {
        for (int i=0; i<n; ++i) scanf ("%lf%lf", &a[i], &b[i]);
        int m;
        scanf ("%d", &m);
        while (m--)
        {
            scanf ("%lf%lf", &p1, &p2);

            if (pnpoly(n,a,b,p1,p2)) printf ("Yes\n");
            else printf ("No\n");
        }
    }
    return 0;
}

HDU 1756 Cupid's Arrow(点在多边形内判定)

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原文地址：http://blog.csdn.net/yangkunpengd/article/details/51352644