Hdu 1247 - Hat’s Words （字典树）

#include<cstdio>
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cmath>
#include<map>
#include <string>
using namespace std;

typedef long long ll;

struct Trie{
Trie *next[26];
int val;
Trie(){
val = -1;
for (int i = 0 ; i < 26 ; i ++)
next[i] = NULL;
}
};

void addword(string& str,Trie* node,int i)
{
if (node->next[str[i]-'a']==NULL)
node->next[str[i]-'a'] = new Trie;

node = node->next[str[i]-'a'];
++i;
if (i<str.size())
addword(str,node,i);
else
{
node->val = 1;
return;
}
}

int query(string & str ,Trie *node,int i)
{
if (node->next[str[i]-'a']==NULL)
return -1;
else
node= node->next[str[i]-'a'];
++i;
if (i<str.size())
return query(str,node,i);
else
return node->val;
}

string str[100000];

int main()
{
int cnt=0;
string p,q;
Trie* head = new Trie;
ios::sync_with_stdio(false);
while (cin>>str[cnt])
{
addword(str[cnt],head,0);
cnt++;
}
sort(str,str+cnt);
for (int i = 0 ; i < cnt ; i ++)
{
p.clear();
q.clear();
for (int j = 0 ; j < str[i].size()-1 ;j ++)
{
p +=str[i][j];
q = str[i].substr(j+1);
//cout<<" p = "<<p<<"  q = "<<q<<endl;
if (query(p,head,0)!=-1&&query(q,head,0)!=-1)
{
cout<<str[i]<<endl;
break;
}
}
}

return 0;
}