hdu 1563

Find your present!

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 4052    Accepted Submission(s): 2674

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
异或解法
#include <iostream>
#include<math.h>
using namespace std;
int main(void)
{
   int n;
   while(cin>>n,n!=0)
   {
   		int m,s=0;
   		for(int i=0;i<n;i++)
   		{
   			cin>>m;
   			s=s^m;
		}
		cout<<s<<endl;
   }
   return 0;
}
MAP解法
 
#include <iostream>
#include<math.h>
#include<algorithm>
#include<memory.h>
#include<map>
using namespace std;
int main()
{
  int n;
  while(cin>>n,n!=0)
  {
  		map<int,int>m;
  		int k;
  		for(int i=0;i<n;i++)
  		{
  		 	cin>>k;
			m[k]++;		
	    }
	    map<int,int>::iterator i;
	    for(i=m.begin();i!=m.end();i++)
	    {
	    	if(i->second==1)
	    		cout<<i->first<<endl;
		}
  }
  	return 0;
}