feat: add C array hash map (krahets#424)

* feat: add C hash map

* fix: hash map put bug

* fix: C array hash map

* fix: Incorrect indentation

* refactory array hash map

* remove header

* refactory print

* 修改注释

* replace all the Tab with 4 spaces

* 向 cpp 靠拢

* 删除错误注释

* delete <stdlib.h>

* delete array_hash_map.h

* Update array_hash_map.c

---------

Co-authored-by: Yudong Jin <[email protected]>

codes/c/CMakeLists.txt

@@ -9,8 +9,9 @@ add_subdirectory(include)
 add_subdirectory(chapter_computational_complexity)
 add_subdirectory(chapter_array_and_linkedlist)
 add_subdirectory(chapter_stack_and_queue)
+add_subdirectory(chapter_heap)
+add_subdirectory(chapter_hashing)
 add_subdirectory(chapter_binary_search)
 add_subdirectory(chapter_tree)
-add_subdirectory(chapter_heap)
 add_subdirectory(chapter_searching)
-add_subdirectory(chapter_sorting)
+add_subdirectory(chapter_sorting)

codes/c/chapter_hashing/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_executable(array_hash_map array_hash_map.c)
+

codes/c/chapter_hashing/array_hash_map.c

@@ -0,0 +1,215 @@
+/**
+ * File: array_hash_map.c
+ * Created Time: 2023-03-18
+ * Author: Guanngxu ([email protected])
+ */
+
+#include "../include/include.h"
+
+/* 哈希表默认数组大小 */
+# define HASH_MAP_DEFAULT_SIZE 100
+
+/* 键值对 int->string */
+struct Entry {
+    int key;
+    char *val;
+};
+
+typedef struct Entry Entry;
+
+/* 用于表示键值对、键、值的集合 */
+struct MapSet {
+    void *set;
+    int len;
+};
+
+typedef struct MapSet MapSet;
+
+/* 基于数组简易实现的哈希表 */
+struct ArrayHashMap {
+    Entry *buckets[HASH_MAP_DEFAULT_SIZE];
+};
+
+typedef struct ArrayHashMap ArrayHashMap;
+
+/* 哈希表初始化函数 */
+ArrayHashMap *newArrayHashMap() {
+    ArrayHashMap *arrayHashMap = malloc(sizeof(ArrayHashMap));
+    return arrayHashMap;
+}
+
+/* 哈希函数 */
+int hashFunc(int key) {
+    int index = key % HASH_MAP_DEFAULT_SIZE;
+    return index;
+}
+
+/* 查询操作 */
+const char *get(const ArrayHashMap *d, const int key) {
+    int index = hashFunc(key);
+    const Entry *pair = d->buckets[index];
+    if (pair == NULL)
+        return NULL;
+    return pair->val;
+}
+
+/* 添加操作 */
+void put(ArrayHashMap *d, const int key, const char *val) {
+    Entry *pair = malloc(sizeof(Entry));
+    pair->key = key;
+    pair->val = malloc(strlen(val) + 1);
+    strcpy(pair->val, val);
+
+    int index = hashFunc(key);
+    d->buckets[index] = pair;
+}
+
+/* 删除操作 */
+void removeItem(ArrayHashMap *d, const int key) {
+    int index = hashFunc(key);
+    free(d->buckets[index]->val);
+    free(d->buckets[index]);
+    d->buckets[index] = NULL;
+}
+
+/* 获取所有键值对 */
+void entrySet(ArrayHashMap *d, MapSet *set) {
+    Entry *entries;
+    int i = 0, index = 0;
+    int total = 0;
+
+    /* 统计有效 entry 数量 */
+    for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+        if (d->buckets[i] != NULL) {
+            total++;
+        }
+    }
+
+    entries = malloc(sizeof(Entry) * total);
+    for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+        if (d->buckets[i] != NULL) {
+            entries[index].key = d->buckets[i]->key;
+            entries[index].val = malloc(strlen(d->buckets[i]->val + 1));
+            strcpy(entries[index].val, d->buckets[i]->val);
+            index++;
+        }
+    }
+
+    set->set = entries;
+    set->len = total;
+}
+
+/* 获取所有键 */
+void keySet(ArrayHashMap *d, MapSet *set) {
+    int *keys;
+    int i = 0, index = 0;
+    int total = 0;
+
+    /* 统计有效 entry 数量 */
+    for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+        if (d->buckets[i] != NULL) {
+            total++;
+        }
+    }
+
+    keys = malloc(total * sizeof(int));
+    for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+        if (d->buckets[i] != NULL) {
+            keys[index] = d->buckets[i]->key;
+            index++;
+        }
+    }
+
+    set->set = keys;
+    set->len = total;
+}
+
+/* 获取所有值 */
+void valueSet(ArrayHashMap *d, MapSet *set) {
+    char **vals;
+    int i = 0, index = 0;
+    int total = 0;
+
+    /* 统计有效 entry 数量 */
+    for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+        if (d->buckets[i] != NULL) {
+            total++;
+        }
+    }
+
+    vals = malloc(total * sizeof(char *));
+    for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+        if (d->buckets[i] != NULL) {
+            vals[index] = d->buckets[i]->val;
+            index++;
+        }
+    }
+
+    set->set = vals;
+    set->len = total;
+}
+
+/* 打印哈希表 */
+void print(ArrayHashMap *d) {
+    int i;
+    MapSet set;
+    entrySet(d, &set);
+    Entry *entries = (Entry*) set.set;
+    for (i = 0; i < set.len; i++) {
+        printf("%d -> %s\n", entries[i].key, entries[i].val);
+    }
+    free(set.set);
+}
+
+/* Driver Code */
+int main() {
+    /* 初始化哈希表 */
+    ArrayHashMap * map = newArrayHashMap();
+
+    /* 添加操作 */
+    // 在哈希表中添加键值对 (key, value)
+    put(map, 12836, "小哈");
+    put(map, 15937, "小啰");
+    put(map, 16750, "小算");
+    put(map, 13276, "小法");
+    put(map, 10583, "小鸭");
+    printf("\n添加完成后，哈希表为\nKey -> Value\n");
+    print(map);
+
+    /* 查询操作 */
+    // 向哈希表输入键 key ，得到值 value
+    const char * name = get(map, 15937);
+    printf("\n输入学号 15937 ，查询到姓名 %s\n", name);
+
+    /* 删除操作 */
+    // 在哈希表中删除键值对 (key, value)
+    removeItem(map, 10583);
+    printf("\n删除 10583 后，哈希表为\nKey -> Value\n");
+    print(map);
+
+    /* 遍历哈希表 */
+    int i;
+
+    printf("\n遍历键值对 Key->Value\n");
+    print(map);
+
+    MapSet set;
+
+    keySet(map, &set);
+    int *keys = (int*) set.set;
+    printf("\n单独遍历键 Key\n");
+    for (i = 0; i < set.len; i++) {
+        printf("%d\n", keys[i]);
+    }
+    free(set.set);
+
+    valueSet(map, &set);
+    char **vals = (char**) set.set;
+    printf("\n单独遍历键 Value\n");
+    for (i = 0; i < set.len; i++) {
+        printf("%s\n", vals[i]);
+    }
+    free(set.set);
+
+    return 0;
+}