Trie树

来源：互联网发布：sql update 指定行编辑：程序博客网时间：2024/05/29 11:58

字典树用于单词统计，查询，非常有用。现在就Trie树给出C语言实现。

#include <stdio.h>#include <malloc.h>#define MAXN  26struct Trie{    int count;   //单词计数    int flag;    // 1表示是单词，0表示不是单词    struct Trie *next[MAXN];};struct Trie *rt;//初始化Trie树void trie_init(){    int i;    rt = (struct Trie*)malloc(sizeof(struct Trie));    rt->count = 0;    rt->flag = 0;    for(i=0; i<MAXN; ++i)        rt->next[i] = NULL;}//插入单词void trie_insert(char *s){    int i;    struct Trie *tmp = rt;    for(s; *s!='\0'; ++s){        if(tmp->next[*s -'a'] == NULL){             struct Trie *cur = (struct Trie*)malloc(sizeof(struct Trie));             cur->count = 0;             cur->flag = 0;             for(i=0; i<MAXN; ++i)                 cur->next[i] = NULL;             tmp->next[*s -'a'] = cur;        }        tmp->count++;        tmp = tmp->next[*s -'a'];    }    tmp->flag = 1;    tmp->count++;}//查询给定字符串前缀的单词数目int trie_search(char *s){    struct Trie *tmp = rt;    for(s; *s!='\0'; ++s){        if(tmp->next[*s -'a'] == NULL)            return 0;        tmp = tmp->next[*s -'a'];    }    return tmp->count;}//删除整个Trie树void trie_del(struct Trie *root){    int i;    for(i=0; i<MAXN; ++i){       if(root->next[i] != NULL)        trie_del(root->next[i]);    }    free(root);}int main(){    int i, n, m;    char ch[15];    FILE *fin;    fin = fopen("input.txt", "r");    while(fscanf(fin, "%d", &n) != EOF){       trie_init();       for(i=0; i<n; ++i){           fscanf(fin, "%s", ch);                    trie_insert(ch);       }       fscanf(fin, "%d", &m);       for(i=0; i<m; ++i){           fscanf(fin, "%s", ch);           printf("%d\n", trie_search(ch));       }       trie_del(rt);    }      return 0;}

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