CodeForces 103A Testing Pants for Sadness

http://codeforces.com/problemset/problem/103/A

看懂题意就可以了 

简单

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	while(cin>>n)
	{
	   long long a[111];
	   for(int i=0;i<n;i++)
	   cin>>a[i];
	   long long ans=0;
	   for(int i=0;i<n;i++)
	   {
	   	ans=ans+(i+1)*a[i]-i;
	   }
	   cout<<ans<<endl;
	}
	return 0;
}