trie tree实验

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

 

#define CHTYPE_NUM (26*2+10+1) /* upper&lower case letter, digital number, underscore */

#define KEY_MAXLEN 64 

 

#define TRUE 1

#define FALSE 0

 

#define OK 0

#define ERROR -1

 

#define DEBUG 0

 

typedef unsigned char UCHAR;

typedef unsigned int UINT;

 

typedef struct _trie_node

{

UCHAR isKey; /* flag whether the node is a keyword */

struct _trie_node* children[CHTYPE_NUM];

}TRIE_NODE;

 

TRIE_NODE *trie_root = NULL;

 

 

int hash_char(char ch)

{

if(ch >= '0' && ch <= '9')

return (ch-'0');

else if(ch >= 'A' && ch <= 'Z')

return (ch-'A'+10);

else if(ch >= 'a' && ch <= 'z')

return (ch-'a'+36);

else if(ch == '_')

return 62;

else

return ERROR;

}

 

char hash_key(int key)

{

if(key >= 0 && key <= 9)

return (key+'0');

else if(key >= 10 && key <= 35)

return (key-10+'A');

else if(key >= 36 && key <= 61)

return (key-36+'a');

else if(key  == 62)

return '_';

else

return '/0';

 

}

 

 

 

int trie_node_init(TRIE_NODE* *node)

{

int i;

(*node)->isKey = FALSE;

for(i = 0; i < CHTYPE_NUM; i++)

{

(*node)->children[i] = NULL;

}

 

return OK;

}

 

 

int trie_tree_init(void)

{

trie_root = (TRIE_NODE*)malloc(sizeof(TRIE_NODE));

printf("trie_root = %p/n", trie_root);

return trie_node_init(&trie_root);

 

#if 0

 

 

if(trie_root == NULL)

{

trie_root = (TRIE_NODE*)malloc(sizeof(TRIE_NODE));

if(trie_root = NULL)

{

printf("malloc error in trie_tree_init()!/n");

return ERROR;

}

trie_root->isKey = FALSE;

trie_root->children = {NULL};

return OK;

}

else

{

printf("the tree root had been initialized, no need to initialized any more!/n");

return ERROR;

}

#endif

}

 

TRIE_NODE* new_node(void)

{

TRIE_NODE *node = NULL;

int i;

node = (TRIE_NODE*)malloc(sizeof(TRIE_NODE));

if(node == NULL)

{

printf("create new node fail!/n");

return NULL;

}

 

node->isKey = FALSE;

for(i = 0; i < CHTYPE_NUM; i++)

{

node->children[i] = NULL;

}

 

return node;

}

 

 

int trie_key_insert(char *key)

{

int i, len, index;

TRIE_NODE* node;

 

node = trie_root;

len = strlen(key);

//inserted = FALSE;

 

for(i = 0; i < len; i++)

{

index = hash_char(key[i]);

if(index == ERROR)

{

printf("hash error!/n");

return ERROR;

}

if(node->children[index] != NULL)

{

if(i == (len-1))

{

printf("duplicated keyword: %s!/n", key);

return ERROR;

} 

node = node->children[index];

continue;

}

else

{

//node->children[index] = (TRIE_NODE*)malloc(sizeof(TRIE_NODE));

//trie_node_init(&(node->children[index]));

node->children[index] = new_node();

node = node->children[index];

if(i == (len-1))

{

node->isKey = TRUE; /* flag it as a keyword now */

printf("keyword [%s] has been inserted!/n", key);

return OK;

}

}

 

}

 

return ERROR;

}

 

/* print all keywords in the trie tree */

int trie_tree_print(void)

{

int i, j, k;

char key[64];

TRIE_NODE *node = trie_root;

 

for(i = 0; i < CHTYPE_NUM; i++)

for(j = 0; j < CHTYPE_NUM; j++)

{

if(node->children[i] != NULL)

{

key[j++] = hash_key(i);

}

}

}

 

 

 

 

 

int trie_key_search(char *key)

{

int i, len, index;

TRIE_NODE *node;

 

 

len = strlen(key);

node = trie_root;

 

for(i = 0; i < len; i++)

{

index = hash_char(key[i]);

if(node->children[index] == NULL)

{

printf("no node!/n");

return ERROR;

}

else

{

#if DEBUG

printf("len = %d/n", len);

printf("node->children[%c] = node->children[%d] = %p/n", key[i], index, node->children[index]);

printf("node->children[%c]->isKey = %d/n", key[i], node->children[index]->isKey);

#endif

if(i == len-1)

{

if((node->children[index])->isKey == TRUE)

{

printf("find key!/n");

return OK;

}

else

{

printf("not a key!/n");

return ERROR;

}

}

else

{

node = node->children[index];

}

}

}

 

printf("find error!/n");

return ERROR;

 

}

 

void trimR(char *buf)

{

int i;

 

for(i = strlen(buf)-1; i >= 0; i--)

{

if(buf[i] == '/n' || buf[i] == ' ' || buf[i] == '/t')

buf[i] = '/0';

}

}

 

 

int main(void)

{

 

char buf[KEY_MAXLEN] = {0};

int ret;

if(trie_tree_init() == OK)

printf("init trie root ok!/n");

 

printf("insert key: ");

while(fgets(buf, KEY_MAXLEN, stdin))

{

trimR(buf);

printf("key = %s/n", buf);

if(buf[0] == '/0')

{

break;

}

if(trie_key_insert(buf) == OK)

{

printf("insert key %s ok!/n", buf);

printf("insert key: ");

}

else

printf("insert key %s fail!/n", buf);

}

 

printf("input key for search: ");

while(fgets(buf, KEY_MAXLEN, stdin))

{

trimR(buf);

if(buf[0] == '/0')

{

break;

}

 

if(trie_key_search(buf) == OK)

printf("search key %s ok/n", buf);

else

printf("search key %s fail/n", buf);

printf("input key for search: ");

 

 

}

 

return 0;

 

}