Another test

Problem 1001 Duplicate Pair

Accept: 5142    Submit: 24343
Time Limit: 1000 mSec    Memory Limit : 65536 KB

Problem Description

An array of length n, with address from 1 to n inclusive, contains entries from the set {1,2,...,n-1} and there's exactly two elements with the same value. Your task is to find out the value.

Input

Input contains several cases.
Each case includes a number n (1<n<=10^6), which is followed by n integers.
The input is ended up with the end of file.

Output

Your must output the value for each case, one per line.

Sample Input

2 1 1 4 1 2 3 2

Sample Output

1 2

Source

IBM Challenge 2004.1 

#include <cstdio>
#include <cstring>
int a[1000005];
int main()
{
    int n;
    while(scanf("%d",&n) != EOF)
    {

        memset(a,0,sizeof a);
        int ans = 0;
        for(int i = 0 ; i < n ; i++)
        {
            int temp;
            scanf("%d",&temp);
            a[temp]++;
            if(a[temp] == 2) ans = temp;
        }
        printf("%d\n",ans);
    }
    return 0;
}