【HDOJ】1247 Hat’s Words

字典树。

#include <cstdio>
#include <cstring>
#include <cstdlib>

#define MAXN 50005
#define MAXL 25

typedef struct Trie {
    bool f;
    Trie *next[26];
    Trie() {
        f = false;
        for (int i=0; i<26; ++i)
            next[i] = NULL;
    }
} Trie;

Trie root;
char map[MAXN][MAXL], buf[MAXL];
int nn = 0;

void create(char str[]) {
    int i = 0, id;
    Trie *p = &root, *q;

    while (str[i]) {
        id = str[i] - 'a';
        ++i;
        if (p->next[id] == NULL) {
            q = new Trie();
            p->next[id] = q;
        }
        p = p->next[id];
    }
    p->f = true;
}

bool find(char str[], int x) {
    int i = 0, id;
    Trie *p = &root;
    bool f;

    while (i<x && str[i]) {
        id = str[i] - 'a';
        ++i;
        if (p->next[id] == NULL)
            return false;
        p = p->next[id];
    }
    f = p->f;
    if (!f) return false;

    p = &root;
    while (str[i]) {
        id = str[i] - 'a';
        ++i;
        if (p->next[id] == NULL)
            return false;
        p = p->next[id];
    }
    return p->f;
}

int main() {
    int i, j, len, n = 0;
    bool f;

    while (scanf("%s", map[n]) != EOF)
        create(map[n++]);

    for (i=0; i<n; ++i) {
        len = strlen(map[i]);
        f = false;
        for (j=1; !f&&j<len-1; ++j)
            f = find(map[i], j);
        if (f)
            printf("%s
", map[i]);
    }

    return 0;
}