题解

#include<iostream>
using namespace std;
int a[100005],s[100005]={0},n,m,R,L;
int main(){
cin>>n>>m;
for(int i=1;i<=n;++i){
cin>>a[i];
s[i]=s[i-1]+a[i];
}
for(int i=1;i<= m;++i){
cin>>R>>L;
cout<<s[L]-s[R-1]<<endl;
}
return 0;
}