Hat’s Words

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)

Problem Description

A hat’s word is a word in the dictionary that is the concatenation of exactly two other words in the dictionary.

You are to find all the hat’s words in a dictionary.

Input

Standard input consists of a number of lowercase words, one per line, in alphabetical order. There will be no more than 50,000 words.

Only one case.

Output

Your output should contain all the hat’s words, one per line, in alphabetical order.

Sample Input

a
ahat
hat
hatword
hziee
word

Sample Output

ahat
hatword

字典树专题的题，用set水过去的。。题意：给一堆字符串，把其中可以由其他两个字符串连接起来的字符串输出。
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cctype>
#include <cmath>
#include <cstdlib>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <list>
using namespace std;
const int INF=1<<27;
const int maxn=5100;
int main()
{
	ios::sync_with_stdio(false);
	string x,a,b;
	set <string> s;
	while(cin>>x)
		s.insert(x);
	set <string>::iterator it=s.begin();
	while(it!=s.end()){
	x=*it;int n=x.size();
	for(int i=0;i<n;i++)
	{
		a.assign(x,0,i+1);
		b.assign(x,i+1,n-i-1);
		if(s.count(a)&&s.count(b))
		{cout<<x<<endl;break;}
	}
	++it;
	}
	return 0;
}