hello-algo/codes/c/chapter_searching/hashing_search.c

147 lines
3.7 KiB
C
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/**
* File: hashing_search.c
* Created Time: 2023-04-15
* Author: Gonglja (glj0@outlook.com)
*/
#include "../utils/common.h"
/* 哈希表 */
struct hashTable {
int key;
void *val;
UT_hash_handle hh; // 基于 uthash.h 实现
};
typedef struct hashTable hashTable;
/* 打印哈希表(当 hashTable 中 val 为 int 型使用这个) */
void printHashTableVal(hashTable **ht) {
struct hashTable *s;
for (s = *ht; s != NULL; s = s->hh.next) {
printf("key: %d: val: %d\n", s->key, *(int *)(s->val));
}
}
/* 打印哈希表(当 hashTable 中 val 为 ListNode* 型使用这个) */
void printHashTableLinklist(hashTable **ht) {
struct hashTable *s;
for (s = *ht; s != NULL; s = s->hh.next) {
printf("key: %d: val: %d\n", s->key, ((ListNode *)s->val)->val);
}
}
/* 哈希表查找 */
hashTable *find(hashTable *ht, int k) {
hashTable *s;
HASH_FIND_INT(ht, &k, s);
return s;
}
/* 添加 k、v 到哈希表 ht 中v 为 int 类型 */
void addInt(hashTable **ht, int k, int v) {
hashTable *s;
HASH_FIND_INT(*ht, &k, s);
if (s == NULL) {
s = malloc(sizeof(*s));
s->key = k;
HASH_ADD_INT(*ht, key, s);
}
int *tmp = malloc(sizeof(*s->val));
*tmp = v;
s->val = tmp;
}
/* 添加 k、v 到哈希表 ht 中v 为 ListNode* 类型 */
void addLinkNode(hashTable **ht, int k, ListNode *v) {
hashTable *s;
HASH_FIND_INT(*ht, &k, s);
if (s == NULL) {
s = malloc(sizeof(*s));
s->key = k;
HASH_ADD_INT(*ht, key, s);
}
s->val = (void *)v;
}
/* 删除 ht 中所有元素 */
void deleteAll(hashTable **ht) {
hashTable *curr, *tmp;
HASH_ITER(hh, *ht, curr, tmp) {
HASH_DEL(*ht, curr);
free(curr);
}
}
/* 通过 key 访问哈希表,返回 int 类型 */
int accessInt(hashTable **h, int key) {
hashTable *s;
int ret = -1;
if (s = find(*h, key)) {
ret = *(int *)s->val;
}
return ret;
}
/* 通过 key 访问哈希表,返回 ListNode* 类型 */
ListNode *accessLinkNode(hashTable **h, int key) {
hashTable *s;
ListNode *res = NULL;
if (s = find(*h, key)) {
res = (ListNode *)s->val;
}
return res;
}
/* 哈希查找(数组) */
int hashingSearchArray(hashTable **ht, int target) {
// 哈希表的 key: 目标元素value: 索引
// 若哈希表中无此 key ,返回 -1
if (find(*ht, target) == NULL)
return -1;
return accessInt(ht, target);
}
/* 哈希查找(链表) */
ListNode *hashingSearchLinkedList(hashTable **ht, int target) {
// 哈希表的 key: 目标节点值value: 节点对象
// 若哈希表中无此 key ,返回 nullptr
if (find(*ht, target) == NULL)
return NULL;
return accessLinkNode(ht, target);
}
/* Driver Code */
int main() {
int target = 3;
/* 哈希查找(数组) */
int nums[] = {1, 5, 3, 2, 4, 7, 5, 9, 10, 8};
// 初始化哈希表
hashTable **ht = malloc(sizeof(*ht));
*ht = NULL;
for (int i = 0; i < sizeof(nums) / sizeof(nums[0]); i++) {
addInt(ht, nums[i], i); // key: 元素value: 索引
}
int index = hashingSearchArray(ht, target);
printf("目标元素 3 的索引 = %d\r\n", index);
deleteAll(ht);
/* 哈希查找(链表) */
ListNode *head = arrToLinkedList(nums, sizeof(nums) / sizeof(nums[0]));
// 初始化哈希表
hashTable **ht1 = malloc(sizeof(*ht));
*ht1 = NULL;
while (head != NULL) {
addLinkNode(ht1, head->val, head); // key: 节点值value: 节点
head = head->next;
}
ListNode *node = hashingSearchLinkedList(ht1, target);
if (node)
printf("目标节点值 3 的对应节点对象为 %#p val: %d\r\n", node, node->val);
deleteAll(ht1);
return 0;
}