https://www.acwing.com/problem/content/description/163/
思路:字典树:①当前串是否为字典树中的前缀:当前串没有申请新的节点,
②树中的某一串是否为当前串的前缀,当前串进过end标记

#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 100010;

int n;
int son[N][10], idx;
bool f[N];

bool insert(char *str)
{
    int p = 0;
    bool has_new = false;
    bool has_found = false;
    for (int i = 0; str[i]; i ++ )
    {
        int u = str[i] - '0';
        if (!son[p][u])
        {
            son[p][u] = ++ idx;
            has_new = true;
        }
        p = son[p][u];
        if (f[p]) has_found = true;
    }

    f[p] = true;

    return has_new && !has_found;
}

int main()
{
    int T;
    cin >> T;
    while (T -- )
    {
        cin >> n;
        memset(son, 0, sizeof son);
        memset(f, false, sizeof f);
        idx = 0;

        bool res = true;

        char str[20];
        for (int i = 0; i < n; i ++ )
        {
            cin >> str;
            if (!insert(str)) res = false;
        }

        if (res) puts("YES");
        else puts("NO");
    }

    return 0;
}

 posted on 2019-08-09 14:36  谁是凶手1703  阅读(50)  评论(0)    收藏  举报