洛谷 P1227 [JSOI2008]完美的对称

#include<iostream>#include<cstdio>#include<algorithm>#include<cstring>#define N 20009using namespace std;int n;struct W{ ???double x,y;}w[N];bool cmp(W a,W b){ ???if(a.x==b.x)return a.y<b.y; ???return a.x<b.x;}int main(){ ???scanf("%d",&n); ???for(int i=1;i<=n;i++){ ???????scanf("%lf%lf",&w[i].x,&w[i].y); ???} ???sort(w+1,w+n+1,cmp); ???double xx=(w[1].x+w[n].x)/2.0; ???double yy=(w[1].y+w[n].y)/2.0; ???for(int i=2;i<=n;i++){ ???????if(n-i+1<=i)break; ???????double tx=(w[i].x+w[n-i+1].x)/2.0; ???????double ty=(w[i].y+w[n-i+1].y)/2.0; ???????if(tx!=xx||ty!=yy){ ???????????printf("This is a dangerous situation!\n"); ???????????return 0; ???????} ???} ???printf("V.I.P. should stay at (%.1lf,%.1lf).",xx,yy); ???return 0;}