题解

#include <iostream>
using namespace std;
int a[10000005];
int s[10000005];
int main(){
int n,m;
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;
}