题解 | 【模板】前缀和

#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n,q;
    cin>>n>>q;
    vector<long long> nums(n);
    vector<long long> sum(n+1);
    for(int i = 0 ; i < n;i++){
        cin>>nums[i];
        //cout<<nums[i]<<endl;
        
    }
    sum[0]=0;
    for(int i = 1 ; i <= n ;i++){
        sum[i] = sum[i-1]+nums[i-1];
        //cout<<sum[i];
        
    }

    for(int i = 0 ; i < q;i++){
        long long t1,t2;
        cin>>t1>>t2;
        //cout<<t1<<"     "<<t2;
        cout<<sum[t2]-sum[t1-1]<<endl;
    }
    return 0;

}
// 64 位输出请用 printf("%lld")