1416: Find the Lost Sock

1416: Find the Lost Sock

Time Limit: 2 Sec  Memory Limit: 128 MB
Submit: 335  Solved: 72
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Description

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

easafgh

aqwerty

easdfgh

easdfgh

aqwerty

aqwerty

2

0x0abcd

0ABCDEF

0x0abcd

Sample Output

aabcdef

easafgh

0ABCDEF

HINT

Source

能用异或算我怎么没想到呢。。。用map，string什么的都稳稳的超时

#include<cstdio>int main(){    int n,i,j;char a[10],b[10];    while(~scanf("%d",&n)){        scanf("%s",a);        for(i=1;i<n*2-1;i++){            scanf("%s",b);for(j=0;j<7;j++)a[j]^=b[j];        }        puts(a);    }}