前綴和模板題
#include<algorithm>
#include<iostream>
#include<cstdio>
using namespace std;
long long a[1001000],s[1001000];
long long n,m,l,r;
int main()
{
freopen("sum.in","r",stdin);
freopen("sum.out","w",stdout);
scanf("%lld %lld",&n,&m);
for(int i=1; i<=n; i++)
{
scanf("%lld",&a[i]);
s[i]=s[i-1]+a[i];
}
for(int i=1; i<=m; i++)
{
scanf("%lld %lld",&l,&r);
printf("%lld\n",s[r]-s[l-1]);
}
return 0;
}