HDU-2086

原题点击打开链接

#include <iostream>#include<cstdio>using namespace std;int main(){int n,i;while(cin>>n){double a[3003],c[3003];cin>>a[0]>>a[n+1];for(i=1; i<=n; i++)cin>>c[i];double sum=0;for(i=n; i>0; i--)sum+=c[i]*(n-i+1);a[1]=(n*a[0]+a[n+1]-sum*2)/(n+1);printf("%.2lf\n",a[1]);}return 0;}