poj3630

trie

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

#define maxl 15
#define maxn 10005

struct Node
{
    Node *next[10];
    bool have;
    bool end;
} trie[maxn * maxl];

int n;
char st[maxl];
int ncount;

bool ins(Node *proot, char *st)
{
    if (proot->end)
        return false;
    if (st[0] == '\0')
    {
        proot->end = true;
        return !proot->have;
    }
    if (!proot->next[st[0] - '0'])
    {
        proot->next[st[0] - '0'] = trie + ncount;
        ncount++;
        proot->have = true;
        ins(proot->next[st[0] - '0'], st + 1);
        return true;
    }
    return ins(proot->next[st[0] - '0'], st + 1);
}

void finish(int a)
{
    int b = n - a - 1;
    for (int i = 0; i < b; i++)
        scanf("%s", st);
}

bool work()
{
    ncount = 1;
    memset(trie, 0, sizeof(trie));
    for (int i = 0; i < n; i++)
    {
        scanf("%s", st);
        if (!ins(trie, st))
        {
            finish(i);
            return false;
        }
    }
    return true;
}

int main()
{
    //freopen("t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    while (t--)
    {
        scanf("%d", &n);
        if (work())
            printf("YES\n");
        else
            printf("NO\n");
    }
    return 0;
}