HDOJ-1671 Phone List(Trie树)

一道字典树的题，这道题在检查每个串时，不仅要判断别的串是否为自己的前缀，还要判断自己是否为其他串的前缀.

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <vector>
#include <climits>
#include <set>
#include <cstdlib>

using namespace std;

#define maxn 10
typedef struct Node{
    bool end;
    Node* p[maxn];
}*T;
T NewNode(){

    T k = (T)malloc(sizeof(Node));
    k -> end = false;
    memset(k -> p, 0, sizeof(k -> p));

    return k;
}
bool Insert(string &s, T u){

    int i = 0;

    while(i < s.size()){

        int m = s[i] - '0';
        if(u -> p[m]){
            u = u -> p[m];
            if(u -> end || i == s.size()-1)
             return false;
        }
        else{
            u -> p[m] = NewNode();
            u = u -> p[m];
        }
        i++;
    }
    u -> end = true;
    return true;
}
void Destory(T u){

    for(int i = 0; i < maxn; i++){
        if(u -> p[i])
         Destory(u -> p[i]); 
    }
    free(u);
}
int main(){

   // freopen("in.txt", "r", stdin);
    int t;

    cin >> t;
    while(t--){

        int n, flag = 0;

        cin >> n;
        T u = NewNode();
        for(int i = 0; i < n; i++){

            string s;

            cin >> s;
            if(!flag && !Insert(s, u))
                      flag = 1;
        } 
        if(flag)
         cout << "NO" << endl;
        else
          cout << "YES" << endl;
        Destory(u);
    } 

    return 0;
}