poj_3630Phone List

Phone List

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 18645		Accepted: 5910

Description

Given a list of phone numbers, determine if it is consistent in the sense that no number is the prefix of another. Let's say the phone catalogue listed these numbers:

• Emergency 911
• Alice 97 625 999
• Bob 91 12 54 26

In this case, it's not possible to call Bob, because the central would direct your call to the emergency line as soon as you had dialled the first three digits of Bob's phone number. So this list would not be consistent.

Input

The first line of input gives a single integer, 1 ≤ t ≤ 40, the number of test cases. Each test case starts with n, the number of phone numbers, on a separate line, 1 ≤ n ≤ 10000. Then follows n lines with one unique phone number on each line. A phone number is a sequence of at most ten digits.

Output

For each test case, output "YES" if the list is consistent, or "NO" otherwise.

Sample Input

2
3
911
97625999
91125426
5
113
12340
123440
12345
98346

Sample Output

NO
YES

#include<iostream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
using namespace std;
#pragma warning(disable : 4996)
const int MAXN = 100000;
const int MAX = 10;

typedef struct Node
{
	bool isstr;
	Node *next[MAX];
}Node, *Trie;
Node node[MAXN];
Trie root;
int cnt;
bool flag;

void insert(char *str)
{
	bool new_flag = false;
	Trie current = root;
	int length = strlen(str);
	for (int i = 0; i < length; i++)
	{
		if(current->isstr == true)  // 前面的串为str的前缀。
		{
			flag = false;
			return;
		}
		int id = str[i] - '0';
		if(current->next[id] == NULL)
		{
			new_flag = true;             //  有新的节点开辟，证明str不为前面的串的前缀。
			node[cnt].isstr = false;    //   新节点的初始化。
			for (int i = 0; i < MAX; i++)
			{
				node[cnt].next[i] = NULL;
			}  
			current->next[id] = &node[cnt++];
		}
		current = current->next[id];
	}
	current->isstr = true;
	if(!new_flag) flag = false;          // str为前面的串的前缀。
}

int main()
{
	freopen("in.txt", "r", stdin);
	int t, n;
	char word[15] = {0};
	scanf("%d", &t);
	while(t --)
	{
		scanf("%d", &n);
		cnt = 0;
		flag = true; //是前面的串的前缀时，flag为false
		root = (Trie)malloc(sizeof(Node));
		for (int i = 0; i < MAX; i++)
		{
			root->next[i] = NULL;
		}
		while(n--)
		{
			scanf("%s", word);
			if(flag)
			{
				insert(word);
			}
		}
		if(flag) printf("YES\n");
		else printf("NO\n");
	}
	return 0;
}