ZOJ 3432 Find the Lost Sock

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
const int maxn = 2000001;
int n;
struct node{
char data[8];
}strs[maxn];
bool cmp(const node & cs1, const node & cs2){
return strcmp(cs1.data, cs2.data) < 0;
}
int main(){
while(scanf("%d\n", &n) == 1){
for(int i = 0; i < n * 2 - 1; ++i){
gets(strs[i].data);
}
sort(strs, strs+ (n * 2 -1), cmp);
for(int i = 0; i < n * 2 - 1; i += 2){
if(strcmp(strs[i].data, strs[i + 1].data)){
printf("%s\n",strs[i].data);
break;
}
}
}
return 0;
}