Trie树

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

#define BRANCH 1
#define LEAF 0

const int MAXN = 256;
const int MAXLEN = 10000;


typedef struct NODE {
    int type;
    int count;
    struct NODE* next[MAXN];
}NODE;

NODE root;

char buffer[MAXLEN];
int pos;

void INSERT(const char* s)
{
    NODE* curr;
    NODE* newnode;
    int len = strlen(s);

    curr = &root;
    for (int i = 0; i < len; i++)
    {
        if ( curr->next[s[i]] == NULL )
        {
            newnode = (NODE *)malloc(sizeof(NODE));
            memset(newnode, 0, sizeof(NODE));
            curr->next[s[i]] = newnode;
            curr->type = BRANCH;
        }
        curr = curr->next[s[i]];
    }
    curr->count += 1;
}

bool SEARCH(const char* s)
{
    NODE* curr;
    int len = strlen(s);
    
    curr = &root;
    for (int i = 0; i < len; i++)
    {
        if ( curr->next[s[i]] == NULL )
            return false;
        curr = curr->next[s[i]];
    }

    if ( i == len && curr->count > 0 )
        return true;
    return false;
}

void WALK(NODE* p)
{
    if ( p->count > 0 )
    {
        buffer[pos] = '\0';
        printf("%s\n",buffer);
        if ( p->type == LEAF )
            return;
    }
    for (int j = 0; j < MAXN; j++)
    {
        if ( p->next[j] != NULL)
        {
            buffer[pos++] = j;
            WALK(p->next[j]);
            pos--;
        }
    }
}


int main()
{
    memset(&root, 0, sizeof(NODE));

    INSERT("MENGMENG");
    INSERT("JIONGJIONG");
    INSERT("JIONG");
    INSERT("AAB");
    INSERT("C");
    INSERT("AABDD");
    INSERT("i am what i am");
    INSERT("AM is my godness");

    pos = 0;
    WALK(&root);

    printf("%d\n",SEARCH("AA"));
    printf("%d\n",SEARCH("AAB"));
    printf("%d\n",SEARCH("AABD"));
    printf("%d\n",SEARCH("AABDD"));

    return 0;
}