#include < iostream > #include < cmath > using namespace std; struct point{ double x,y; point ( double xx = 0 , double yy = 0 ){ x = xx; y = yy; } double operator * (point b){ return x * b.y - y * b.x; }}p[ 1000001 ]; int main(){ int T,N,i; scanf( " %d " , & T); while (T -- ) { scanf( " %d " , & N); for (i = 0 ;i < N;i ++ ) scanf( " %lf%lf " , & p[i].x, & p[i].y); p[N].x = p[ 0 ].x; p[N].y = p[ 0 ].y; double area = 0 ; point re; for (i = 0 ;i < N;i ++ ) { area += p[i] * p[i + 1 ]; re.x += (p[i].x + p[i + 1 ].x) * (p[i] * p[i + 1 ]); re.y += (p[i].y + p[i + 1 ].y) * (p[i] * p[i + 1 ]); } area /= 2 ; re.x /= 6 * area; re.y /= 6 * area; printf( " %.2lf %.2lf\n " ,re.x,re.y); } return 0 ;}
转载于:https://www.cnblogs.com/DreamUp/archive/2010/08/28/1811431.html
相关资源：JAVA上百实例源码以及开源项目