From 265097e5fbf81bce5fc87a8e6aa62cd3e7f7539f Mon Sep 17 00:00:00 2001 From: krahets Date: Fri, 13 Oct 2023 14:35:09 +0800 Subject: [PATCH] build --- docs/chapter_hashing/hash_collision.md | 257 +++++++++++++++++++++---- docs/index.md | 2 +- 2 files changed, 217 insertions(+), 42 deletions(-) diff --git a/docs/chapter_hashing/hash_collision.md b/docs/chapter_hashing/hash_collision.md index 7ae3a6453..59752d5f0 100644 --- a/docs/chapter_hashing/hash_collision.md +++ b/docs/chapter_hashing/hash_collision.md @@ -1164,24 +1164,24 @@ comments: true hashMapChaining *newHashMapChaining() { // 为哈希表分配空间 int tableSize = 4; - hashMapChaining *hashmap = (hashMapChaining *)malloc(sizeof(hashMapChaining)); + hashMapChaining *hashMap = (hashMapChaining *)malloc(sizeof(hashMapChaining)); // 初始化数组 - hashmap->buckets = (Pair *)malloc(sizeof(Pair) * tableSize); - memset(hashmap->buckets, 0, sizeof(Pair) * tableSize); + hashMap->buckets = (Pair *)malloc(sizeof(Pair) * tableSize); + memset(hashMap->buckets, 0, sizeof(Pair) * tableSize); - hashmap->capacity = tableSize; - hashmap->size = 0; - hashmap->extendRatio = 2; - hashmap->loadThres = 2.0 / 3.0; + hashMap->capacity = tableSize; + hashMap->size = 0; + hashMap->extendRatio = 2; + hashMap->loadThres = 2.0 / 3.0; - return hashmap; + return hashMap; } /* 销毁哈希表 */ - void delHashMapChaining(hashMapChaining *hashmap) { - for (int i = 0; i < hashmap->capacity; i++) { - Pair *pair = &hashmap->buckets[i]; + void delHashMapChaining(hashMapChaining *hashMap) { + for (int i = 0; i < hashMap->capacity; i++) { + Pair *pair = &hashMap->buckets[i]; Node *node = pair->node; while (node != NULL) { Node *temp = node; @@ -1190,26 +1190,40 @@ comments: true free(temp); } } - free(hashmap->buckets); - free(hashmap); + free(hashMap->buckets); + free(hashMap); } /* 哈希函数 */ - int hashFunc(hashMapChaining *hashmap, const int key) { - return key % hashmap->capacity; + int hashFunc(hashMapChaining *hashMap, const int key) { + return key % hashMap->capacity; } /* 负载因子 */ - double loadFactor(hashMapChaining *hashmap) { - return (double)hashmap->size / (double)hashmap->capacity; + double loadFactor(hashMapChaining *hashMap) { + return (double)hashMap->size / (double)hashMap->capacity; + } + + /* 查询操作 */ + char *get(hashMapChaining *hashMap, const int key) { + int index = hashFunc(hashMap, key); + Pair *pair = &hashMap->buckets[index]; + Node *node = pair->node; + while (node != NULL) { + if (node->key == key) { + return node->val; + } + node = node->next; + } + return NULL; } /* 添加操作 */ - void put(hashMapChaining *hashmap, const int key, char *val) { - if (loadFactor(hashmap) > hashmap->loadThres) { - extend(hashmap); + void put(hashMapChaining *hashMap, const int key, char *val) { + if (loadFactor(hashMap) > hashMap->loadThres) { + extend(hashMap); } - int index = hashFunc(hashmap, key); + int index = hashFunc(hashMap, key); // 先为新节点分配空间再赋值 Node *newNode = (Node *)malloc(sizeof(Node)); @@ -1219,11 +1233,11 @@ comments: true strcpy(newNode->val, val); newNode->val[strlen(val)] = '\0'; - Pair *pair = &hashmap->buckets[index]; + Pair *pair = &hashMap->buckets[index]; Node *node = pair->node; if (node == NULL) { - hashmap->buckets[index].node = newNode; - hashmap->size++; + hashMap->buckets[index].node = newNode; + hashMap->size++; return; } while (node != NULL) { @@ -1242,13 +1256,13 @@ comments: true node = node->next; } node->next = newNode; - hashmap->size++; + hashMap->size++; } /* 删除操作 */ - void removeItem(hashMapChaining *hashmap, int key) { - int index = hashFunc(hashmap, key); - Pair *pair = &hashmap->buckets[index]; + void removeItem(hashMapChaining *hashMap, int key) { + int index = hashFunc(hashMap, key); + Pair *pair = &hashMap->buckets[index]; Node *node = pair->node; // 保存后继的节点 Node *prev = NULL; @@ -1263,7 +1277,7 @@ comments: true // 释放内存 free(node->val); free(node); - hashmap->size--; + hashMap->size--; return; } prev = node; @@ -1273,22 +1287,22 @@ comments: true } /* 扩容哈希表 */ - void extend(hashMapChaining *hashmap) { + void extend(hashMapChaining *hashMap) { // 暂存原哈希表 - Pair *oldBuckets = hashmap->buckets; - int oldCapacity = hashmap->capacity; + Pair *oldBuckets = hashMap->buckets; + int oldCapacity = hashMap->capacity; // 创建新的哈希表，重新分配一段空间 - hashmap->capacity *= hashmap->extendRatio; - hashmap->buckets = (Pair *)malloc(sizeof(Pair) * hashmap->capacity); - memset(hashmap->buckets, 0, sizeof(Pair) * hashmap->capacity); - hashmap->size = 0; + hashMap->capacity *= hashMap->extendRatio; + hashMap->buckets = (Pair *)malloc(sizeof(Pair) * hashMap->capacity); + memset(hashMap->buckets, 0, sizeof(Pair) * hashMap->capacity); + hashMap->size = 0; // 将原哈希表中的键值对重新哈希到新的哈希表中 for (int i = 0; i < oldCapacity; i++) { Node *node = oldBuckets[i].node; while (node != NULL) { - put(hashmap, node->key, node->val); + put(hashMap, node->key, node->val); node = node->next; } } @@ -1307,10 +1321,10 @@ comments: true } /* 打印哈希表 */ - void print(hashMapChaining *hashmap) { - for (int i = 0; i < hashmap->capacity; i++) { + void print(hashMapChaining *hashMap) { + for (int i = 0; i < hashMap->capacity; i++) { printf("["); - Pair *pair = &hashmap->buckets[i]; + Pair *pair = &hashMap->buckets[i]; Node *node = pair->node; while (node != NULL) { if (node->val != NULL) { @@ -2656,7 +2670,168 @@ comments: true === "C" ```c title="hash_map_open_addressing.c" - [class]{hashMapOpenAddressing}-[func]{} + /* 开放寻址哈希表 */ + struct hashMapOpenAddressing { + int size; // 键值对数量 + int capacity; // 哈希表容量 + double loadThres; // 触发扩容的负载因子阈值 + int extendRatio; // 扩容倍数 + Pair **buckets; // 桶数组 + Pair *TOMBSTONE; // 删除标记 + }; + + typedef struct hashMapOpenAddressing hashMapOpenAddressing; + + /* 构造方法 */ + hashMapOpenAddressing *newHashMapOpenAddressing() { + hashMapOpenAddressing *hashMap = (hashMapOpenAddressing *)malloc(sizeof(hashMapOpenAddressing)); + hashMap->size = 0; + hashMap->capacity = 4; + hashMap->loadThres = 2.0 / 3.0; + hashMap->extendRatio = 2; + hashMap->buckets = (Pair **)malloc(sizeof(Pair *) * hashMap->capacity); + hashMap->TOMBSTONE = (Pair *)malloc(sizeof(Pair)); + hashMap->TOMBSTONE->key = -1; + hashMap->TOMBSTONE->val = "-1"; + + return hashMap; + } + + /* 析构方法 */ + void delHashMapOpenAddressing(hashMapOpenAddressing *hashMap) { + for (int i = 0; i < hashMap->capacity; i++) { + Pair *pair = hashMap->buckets[i]; + if (pair != NULL && pair != hashMap->TOMBSTONE) { + free(pair->val); + free(pair); + } + } + } + + /* 哈希函数 */ + int hashFunc(hashMapOpenAddressing *hashMap, int key) { + return key % hashMap->capacity; + } + + /* 负载因子 */ + double loadFactor(hashMapOpenAddressing *hashMap) { + return (double)hashMap->size / (double)hashMap->capacity; + } + + /* 搜索 key 对应的桶索引 */ + int findBucket(hashMapOpenAddressing *hashMap, int key) { + int index = hashFunc(hashMap, key); + int firstTombstone = -1; + // 线性探测，当遇到空桶时跳出 + while (hashMap->buckets[index] != NULL) { + // 若遇到 key ，返回对应桶索引 + if (hashMap->buckets[index]->key == key) { + // 若之前遇到了删除标记，则将键值对移动至该索引 + if (firstTombstone != -1) { + hashMap->buckets[firstTombstone] = hashMap->buckets[index]; + hashMap->buckets[index] = hashMap->TOMBSTONE; + return firstTombstone; // 返回移动后的桶索引 + } + return index; // 返回桶索引 + } + // 记录遇到的首个删除标记 + if (firstTombstone == -1 && hashMap->buckets[index] == hashMap->TOMBSTONE) { + firstTombstone = index; + } + // 计算桶索引，越过尾部返回头部 + index = (index + 1) % hashMap->capacity; + } + // 若 key 不存在，则返回添加点的索引 + return firstTombstone == -1 ? index : firstTombstone; + } + + /* 查询操作 */ + char *get(hashMapOpenAddressing *hashMap, int key) { + // 搜索 key 对应的桶索引 + int index = findBucket(hashMap, key); + // 若找到键值对，则返回对应 val + if (hashMap->buckets[index] != NULL && hashMap->buckets[index] != hashMap->TOMBSTONE) { + return hashMap->buckets[index]->val; + } + // 若键值对不存在，则返回空字符串 + return ""; + } + + /* 添加操作 */ + void put(hashMapOpenAddressing *hashMap, int key, char *val) { + // 当负载因子超过阈值时，执行扩容 + if (loadFactor(hashMap) > hashMap->loadThres) { + extend(hashMap); + } + // 搜索 key 对应的桶索引 + int index = findBucket(hashMap, key); + // 若找到键值对，则覆盖 val 并返回 + if (hashMap->buckets[index] != NULL && hashMap->buckets[index] != hashMap->TOMBSTONE) { + free(hashMap->buckets[index]->val); + hashMap->buckets[index]->val = (char *)malloc(sizeof(strlen(val + 1))); + strcpy(hashMap->buckets[index]->val, val); + hashMap->buckets[index]->val[strlen(val)] = '\0'; + return; + } + // 若键值对不存在，则添加该键值对 + Pair *pair = (Pair *)malloc(sizeof(Pair)); + pair->key = key; + pair->val = (char *)malloc(sizeof(strlen(val + 1))); + strcpy(pair->val, val); + pair->val[strlen(val)] = '\0'; + + hashMap->buckets[index] = pair; + hashMap->size++; + } + + /* 删除操作 */ + void removeItem(hashMapOpenAddressing *hashMap, int key) { + // 搜索 key 对应的桶索引 + int index = findBucket(hashMap, key); + // 若找到键值对，则用删除标记覆盖它 + if (hashMap->buckets[index] != NULL && hashMap->buckets[index] != hashMap->TOMBSTONE) { + Pair *pair = hashMap->buckets[index]; + free(pair->val); + free(pair); + hashMap->buckets[index] = hashMap->TOMBSTONE; + hashMap->size--; + } + } + + /* 扩容哈希表 */ + void extend(hashMapOpenAddressing *hashMap) { + // 暂存原哈希表 + Pair **bucketsTmp = hashMap->buckets; + int oldCapacity = hashMap->capacity; + // 初始化扩容后的新哈希表 + hashMap->capacity *= hashMap->extendRatio; + hashMap->buckets = (Pair **)malloc(sizeof(Pair *) * hashMap->capacity); + hashMap->size = 0; + // 将键值对从原哈希表搬运至新哈希表 + for (int i = 0; i < oldCapacity; i++) { + Pair *pair = bucketsTmp[i]; + if (pair != NULL && pair != hashMap->TOMBSTONE) { + put(hashMap, pair->key, pair->val); + free(pair->val); + free(pair); + } + } + free(bucketsTmp); + } + + /* 打印哈希表 */ + void print(hashMapOpenAddressing *hashMap) { + for (int i = 0; i < hashMap->capacity; i++) { + Pair *pair = hashMap->buckets[i]; + if (pair == NULL) { + printf("NULL\n"); + } else if (pair == hashMap->TOMBSTONE) { + printf("TOMBSTONE\n"); + } else { + printf("%d -> %s\n", pair->key, pair->val); + } + } + } ``` === "Zig" diff --git a/docs/index.md b/docs/index.md index 14d8b9cd3..fe67fe1ef 100644 --- a/docs/index.md +++ b/docs/index.md @@ -59,7 +59,7 @@ hide:

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