字典树, 字符串排序，Trie

Trie，字典树，字符串排序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_N 26
typedef struct Node {
        int flag;
        struct Node *next[MAX_N];
} Node;
                                                                                                                                                                                                                                             
void clear(Node *root) {                                                                                                                                                                                                                     
        if (!root) return ;                                                                                                                                                                                                                  
        for (int i = 1; i < MAX_N; i++) clear(root->next[i]);                                                                                                                                                                                
        free(root);                                                                                                                                                                                                                          
        return ;                                                                                                                                                                                                                             
}                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                             
Node *getNewNode() {                                                                                                                                                                                                                         
        Node *p = (Node *)malloc(sizeof(Node));                                                                                                                                                                                              
        p->flag = 0;                                                                                                                                                                                                                         
        for (int i = 0; i < MAX_N; i++) p->next[i] = 0;                                                                                                                                                                                      
        return p;                                                                                                                                                                                                                            
}                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                             
Node *insert(Node *root, char *a) {                                                                                                                                                                                                          
        if (!root) root = getNewNode();                                                                                                                                                                                                      
        Node *p = root;                                                                                                                                                                                                                      
        for (int i = 0; a[i]; i++) {                                                                                                                                                                                                         
                p->next[a[i] - 'a'] || (p->next[a[i] - 'a'] = getNewNode());                                                                                                                                                                 
                p = p->next[a[i] - 'a'];                                                                                                                                                                                                     
                                                                                                                                                                                                                                             
        }                                                                                                                                                                                                                                    
        p->flag = 1;                                                                                                                                                                                                                         
        return root;                                                                                                                                                                                                                         
}                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                             
int fin(Node *root, char *a, int s) {                                                                                                                                                                                                        
        if (!root) return 0;                                                                                                                                                                                                                 
        if (!s && root->flag) return 1;                                                                                                                                                                                                      
        return fin(root->next[a[0] - 'a'], a + 1, s - 1);                                                                                                                                                                                    
}                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                             
void output(Node *root, char *c, int s) {                                                                                                                                                                                                    
        if (!root) return ;
        root->flag && (c[s] = 0, printf("%s
", c));
        for (int i = 0; i < MAX_N; i++) {
               c[s] = i + 'a';
               root->next[i] && (output(root->next[i], c, s + 1), 0);
        }
        return ;
}

int main() {
        int op;
        char buff[1000] = {0};
        Node *root = getNewNode();
        while (~scanf("%d", &op)) {
                op - 2 && scanf("%s", buff);
                switch (op) {
                        case 2: printf("排序: 
"), output(root, buff, 0); break;
                        case 0: printf("
插入%s
", buff), insert(root, buff); break;
                        case 1: printf("
查找%s == %d
", buff, fin(root, buff, strlen(buff)));
                }
        }
        return 0;
}