CSES – Static Range Sum Queries

#include<bits/stdc++.h>
#define int long long
#define fastio ios_base::sync_with_stdio(false);cin.tie(0)
using namespace std;
int n,q;
vector<int>v,pre;
signed main(){
    fastio;
    cin>>n>>q;
    for(int i=0;i<n;i++){
        int x; cin>>x;
        v.push_back(x);
    }
    pre.push_back(0);
    for(int i=1;i<=n;i++){
        pre.push_back(pre[i-1] + v[i-1]);
    }
    while(q--){
        int L,R; cin>>L>>R;
        cout<<pre[R]-pre[L-1]<<"\n";
    }
    return 0;
}