水题,根本不用凸包,就是一简单的极角排序。
叉乘<0,逆时针。
#include <iostream> #include <cstdio> #include <cstring> #include <string> #include <algorithm> using namespace std; const int maxn=55; struct point { double x,y; } p[maxn]; double cross(point c1,point b1,point a2) { return (b1.x-c1.x)*(a2.y-c1.y)-(b1.y-c1.y)*(a2.x-c1.x); } bool cmp(point a,point b) { point c; c.x=0;c.y=0; return cross(c,b,a)<0; } int main() { int n=0; while(scanf("%lf %lf",&p[n].x,&p[n].y)!=EOF) n++; sort(p+1,p+n, cmp); for(int i =0; i<n; i++) cout<<"("<<p[i].x<<","<<p[i].y<<")"<<endl; return 0; }
时间: 2024-11-09 03:20:52