ZOJ 3432  Find the Lost Sock

E - Find the Lost Sock _p

Time Limit: 2000MS

Memory Limit: 65536K

64bit IO Format: %lld & %llu

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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
eas fgh
aqwerty
easdfgh
easdfgh
aqwerty
aqwerty
2
0x0abcd
0ABCDEF
0x0abcd

Sample Output

aabcdef
eas fgh
0ABCDEF

Hint

Because of HUGE input, scanf is recommended.  

这题一般的解法基本都会超时的，所以不要想暴力解决，刚开学的时候学了个异或运算，没想到竟然也能用上了，呵呵（袜子真的挺好看的！）

代码：

#include<stdio.h>

#include<string.h>

int num[8];

char s[8];

int main()

{

int n,i,k;

while(scanf("%d",&n)!=EOF)

{

getchar();

memset(num,0,sizeof(num));

k=0;

n=n*2-2;

gets(s);

for(i=0;i<7;i++)

{

k=s[i];

num[i]=k;

}

while(n--)

{

gets(s);

for(i=0;i<7;i++)

{

k=s[i];

num[i]=num[i]^k;

}

}

for(k=0;k<7;k++)

printf("%c",num[k]);

printf("\n");

}

return 0;

}