795. 前缀和

Posted 2021-05-20 幽殇默

https://www.acwing.com/problem/content/description/797/

#include<cstdio>
#include<iostream>
using namespace std;
const int N=1e5+10;
int a[N],s[N];
int n,m;
int main(void)
{
    cin>>n>>m;
    for(int i=1;i<=n;i++) cin>>a[i],s[i]=s[i-1]+a[i];
    while(m--)
    {
        int l,r; cin>>l>>r;
        cout<<s[r]-s[l-1]<<endl;
    }
    return 0;
}