HDOJ 1247 Hat’s Words（trie树入门）

题意：

问一个字符串是否由字典里面的两个字符串组成。

思路：

字典树：建树，枚举

 

#include <iostream> using namespace std; struct node { bool isword; int child[26]; } trie[100010]; char dict[50010][21]; int size = 0; void Insert(const char* word, int rt) { if (*word == '\0') {

        trie[rt].isword = true; return ; } int m = *word - 'a'; if (trie[rt].child[m]) {

        Insert(word + 1, trie[rt].child[m]); } else {

        trie[rt].child[m] = ++size;

        Insert(word + 1, size); } } bool Query(const char* word, int rt) { if (*word == '\0') return trie[rt].isword; int m = *word - 'a'; if (!trie[rt].child[m]) return false; else return Query(word + 1, trie[rt].child[m]); } int main() { int n = 0; while (scanf("%s", dict[n]) != EOF)

        Insert(dict[n++], 0); char word[21]; for (int i = 0; i < n; ++i) { bool flag = false; for (int j = 0; dict[i][j+1] != '\0'; ++j) { if (flag) break;

            word[j] = dict[i][j];

            flag = Query(word, 0) && Query(&dict[i][j+1], 0); } if (flag)

            printf("%s\n", dict[i]);

        memset(word, 0, sizeof(word)); } return 0; }