#include<stdio.h>
#include<stdlib.h>
int main()
{
    int m,n,a[50000],b[50000],i,j,p,c;
    scanf("%d",&n);
    for(i=0;i<n;i++)
    {
        scanf("%d",&a[i]);
    }
    scanf("%d",&m);
    for(i=0;i<m;i++)
    {
        scanf("%d",&b[i]);
    }
    for(j=0;j<n;j++)
    {
        for(p=0;p<m;p++)
        {
            c=a[j]+b[p];

            if(c==10000)
            {
                 printf("YES");
                 exit(0);
            }
        }
    }
    printf("NO");
    return 0;
}

in my mind, two loops is not required. Try to use binary search in sorted array.
steps:
1.Take from first array the number;
2.1000-[this number]
3.find 1000-[this number] in second array(use binary search)

This way, you have only one loop.

Edited by author 20.11.2015 23:45

Edited by author 20.11.2015 23:45

Thanks a lot!!!