#include <iostream.h>
int main()
{
    int mas[10000],x,k=0,p,sum=0,a[5000];
    unsigned long int i,j,Q,N;
    cin>>N;
    for(p=1;p<=N;p++)
    {
        cin>>a[p];
    }
    cin>>Q;
    for(x=1;x<=Q;x++)
    {
        sum=0;
        cin>>i>>j;
        for(p=i;p<=j;p++)
        {
            sum+=a[p];
        }
        mas[k]=sum;
        k++;
    }
    for(p=0;p<Q;p++)
        cout<<mas[p]<<endl;
    return 0;
}

Use DP.

DEAR MASTER OF C++!!!DON'T COUNT SUM!!!INSTEAD OF COUNT SUM USE: a[k]=a[k]+a[k-1];
AND AT ANOTHER CYCLE
for(x=1;x<=Q;x++)
USE b[k]=a[j]-a[i-1];
    cout<<b[k]<<endl;
DON'T USE SUM!
GOOD LUCK!!!!!