hdu 1563 Find your present!

Find your present!

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 3579    Accepted Submission(s): 2386

Problem Description

In the new year party, everybody will get a "special present".Now it's your turn to get your special present, a lot of presents now putting on the desk, and only one of them will be yours.Each present has a card number on it, and your present's card number will be the one that different from all the others.For example, there are 5 present, and their card numbers are 1, 2, 3, 2, 1.so your present will be the one with the card number of 3, because 3 is the number that different from all the others.

 

Input

The input file will consist of several cases.   Each case will be presented by an integer n (1<=n<=200, and n is odd) at first. Following that, n positive integers will be given in a line. These numbers indicate the card numbers of the presents.n = 0 ends the input.

 

Output

For each case, output an integer in a line, which is the card number of your present.

 

Sample Input

5

1 1 3 2 2

3

1 2 1

0

 

Sample Output

3

2

位运算：

#include <iostream>
using namespace std;

int main(){
    int n, num;
    while(cin >> n && n != 0){
        int ans = 0;
        for(int i = 0; i < n; i++){
            cin >> num;
            ans = ans ^ num;
        }
        cout << ans << endl;    
    }
    return 0;
}