ZOJ 3432 Find the Lost Sock （异或的运用）

Alice bought a lot of pairs of socks yesterday. But when she went home, she found that she has lost one of them. Each sock has a name which contains exactly 7 charaters.

Alice wants to know which sock she has lost. Maybe you can help her.

Input

There are multiple cases. The first line containing an integer n (1 <= n <= 1000000) indicates that Alice bought n pairs of socks. For the following 2*n-1 lines, each line is a string with 7 charaters indicating the name of the socks that Alice took back.

Output

The name of the lost sock.

Sample Input

2
aabcdef
bzyxwvu
bzyxwvu
4
aqwerty
eas fgh
aqwerty
easdfgh
easdfgh
aqwerty
aqwerty
2
0x0abcd
0ABCDEF
0x0abcd

Sample Output

aabcdef
eas fgh
0ABCDEF

题意：

有2*n-1个袜子，叫你找出不能配对的那个袜子。

 

 

只有一个出现奇数次，答案就是它了：

 

#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<cstring>
#include<memory.h>
using namespace std;
char s[10],c;
int main()
{
    int n;
    while(~scanf("%d\n",&n)){
        for(int i=0;i<=7;i++) s[i]='\0';
        for(int i=1;i<2*n;i++){
            for(int j=0;j<8;j++){
                c=getchar();
                s[j]=s[j]^c;
            }
        }
        printf("%s",s);
    }
    return 0;
}