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Add kotlin code for the chapter of hashing (#1104)
* feat(kotlin): add kotlin code for dynamic programming. * Update knapsack.kt * feat(kotlin): add kotlin codes for graph. * style(kotlin): reformatted the codes. * feat(kotlin): add kotlin codes for the chapter of greedy. * Update max_product_cutting.kt * feat(kotlin): add kotlin code for chapter of hashing. * style(kotlin): modified some comment * Update array_hash_map.kt * Update hash_map_chaining.kt * Update hash_map_chaining.kt
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curtishd
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130
codes/kotlin/chapter_hashing/array_hash_map.kt
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130
codes/kotlin/chapter_hashing/array_hash_map.kt
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/**
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* File: array_hash_map.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_hashing
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/* 键值对 */
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class Pair(
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var key: Int,
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var value: String
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)
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/* 基于数组实现的哈希表 */
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class ArrayHashMap {
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private val buckets = arrayOfNulls<Pair>(100)
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/* 构造方法 */
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init {
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// 初始化数组，包含 100 个桶
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for (i in 0..<100) {
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buckets[i] = null
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}
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}
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/* 哈希函数 */
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fun hashFunc(key: Int): Int {
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val index = key % 100
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return index
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}
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/* 查询操作 */
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fun get(key: Int): String? {
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val index = hashFunc(key)
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val pair = buckets[index] ?: return null
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return pair.value
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}
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/* 添加操作 */
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fun put(key: Int, value: String) {
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val pair = Pair(key, value)
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val index = hashFunc(key)
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buckets[index] = pair
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}
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/* 删除操作 */
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fun remove(key: Int) {
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val index = hashFunc(key)
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// 置为 null ，代表删除
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buckets[index] = null
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}
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/* 获取所有键值对 */
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fun pairSet(): MutableList<Pair> {
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val pairSet = ArrayList<Pair>()
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for (pair in buckets) {
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if (pair != null) pairSet.add(pair)
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}
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return pairSet
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}
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/* 获取所有键 */
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fun keySet(): MutableList<Int> {
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val keySet = ArrayList<Int>()
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for (pair in buckets) {
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if (pair != null) keySet.add(pair.key)
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}
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return keySet
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}
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/* 获取所有值 */
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fun valueSet(): MutableList<String> {
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val valueSet = ArrayList<String>()
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for (pair in buckets) {
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pair?.let { valueSet.add(it.value) }
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}
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return valueSet
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}
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/* 打印哈希表 */
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fun print() {
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for (kv in pairSet()) {
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val key = kv.key
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val value = kv.value
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println("${key}->${value}")
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}
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}
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}
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/* Driver Code */
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fun main() {
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/* 初始化哈希表 */
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val map = ArrayHashMap()
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/* 添加操作 */
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// 在哈希表中添加键值对 (key, value)
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map.put(12836, "小哈")
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map.put(15937, "小啰")
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map.put(16750, "小算")
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map.put(13276, "小法")
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map.put(10583, "小鸭")
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println("\n添加完成后，哈希表为\nKey -> Value")
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map.print()
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/* 查询操作 */
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// 向哈希表中输入键 key ，得到值 value
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val name: String? = map.get(15937)
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println("\n输入学号 15937 ，查询到姓名 $name")
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/* 删除操作 */
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// 在哈希表中删除键值对 (key, value)
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map.remove(10583)
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println("\n删除 10583 后，哈希表为\nKey -> Value")
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map.print()
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/* 遍历哈希表 */
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println("\n遍历键值对 Key->Value")
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for (kv in map.pairSet()) {
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println("${kv.key} -> ${kv.value}")
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}
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println("\n单独遍历键 Key")
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for (key in map.keySet()) {
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println(key)
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}
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println("\n单独遍历值 Value")
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for (value in map.valueSet()) {
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println(value)
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}
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}
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36
codes/kotlin/chapter_hashing/built_in_hash.kt
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36
codes/kotlin/chapter_hashing/built_in_hash.kt
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/**
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* File: built_in_hash.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_hashing
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import utils.ListNode
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/* Driver Code */
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fun main() {
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val num = 3
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val hashNum = Integer.hashCode(num)
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println("整数 $num 的哈希值为 $hashNum")
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val bol = true
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val hashBol = Boolean.hashCode()
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println("布尔量 $bol 的哈希值为 $hashBol")
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val dec = 3.14159
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val hashDec = java.lang.Double.hashCode(dec)
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println("小数 $dec 的哈希值为 $hashDec")
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val str = "Hello 算法"
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val hashStr = str.hashCode()
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println("字符串 $str 的哈希值为 $hashStr")
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val arr = arrayOf<Any>(12836, "小哈")
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val hashTup = arr.contentHashCode()
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println("数组 ${arr.contentToString()} 的哈希值为 ${hashTup}")
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val obj = ListNode(0)
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val hashObj = obj.hashCode()
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println("节点对象 $obj 的哈希值为 $hashObj")
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}
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50
codes/kotlin/chapter_hashing/hash_map.kt
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50
codes/kotlin/chapter_hashing/hash_map.kt
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/**
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* File: hash_map.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_hashing
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import utils.printHashMap
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/* Driver Code */
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fun main() {
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/* 初始化哈希表 */
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val map: MutableMap<Int, String> = HashMap()
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/* 添加操作 */
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// 在哈希表中添加键值对 (key, value)
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map[12836] = "小哈"
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map[15937] = "小啰"
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map[16750] = "小算"
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map[13276] = "小法"
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map[10583] = "小鸭"
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println("\n添加完成后，哈希表为\nKey -> Value")
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printHashMap(map)
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/* 查询操作 */
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// 向哈希表中输入键 key ，得到值 value
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val name = map[15937]
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println("\n输入学号 15937 ，查询到姓名 $name")
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/* 删除操作 */
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// 在哈希表中删除键值对 (key, value)
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map.remove(10583)
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println("\n删除 10583 后，哈希表为\nKey -> Value")
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printHashMap(map)
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/* 遍历哈希表 */
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println("\n遍历键值对 Key->Value")
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for ((key, value) in map) {
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println("$key -> $value")
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}
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println("\n单独遍历键 Key")
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for (key in map.keys) {
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println(key)
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}
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println("\n单独遍历值 Value")
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for (value in map.values) {
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println(value)
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}
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}
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145
codes/kotlin/chapter_hashing/hash_map_chaining.kt
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145
codes/kotlin/chapter_hashing/hash_map_chaining.kt
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/**
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* File: hash_map_chaining.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_hashing
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/* 链式地址哈希表 */
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class HashMapChaining() {
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var size: Int // 键值对数量
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var capacity: Int // 哈希表容量
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val loadThres: Double // 触发扩容的负载因子阈值
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val extendRatio: Int // 扩容倍数
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var buckets: MutableList<MutableList<Pair>> // 桶数组
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/* 构造方法 */
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init {
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size = 0
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capacity = 4
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loadThres = 2.0 / 3.0
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extendRatio = 2
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buckets = ArrayList(capacity)
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for (i in 0..<capacity) {
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buckets.add(mutableListOf())
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}
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}
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/* 哈希函数 */
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fun hashFunc(key: Int): Int {
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return key % capacity
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}
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/* 负载因子 */
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fun loadFactor(): Double {
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return (size / capacity).toDouble()
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}
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/* 查询操作 */
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fun get(key: Int): String? {
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val index = hashFunc(key)
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val bucket = buckets[index]
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// 遍历桶，若找到 key ，则返回对应 val
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for (pair in bucket) {
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if (pair.key == key) return pair.value
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}
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// 若未找到 key ，则返回 null
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return null
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}
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/* 添加操作 */
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fun put(key: Int, value: String) {
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// 当负载因子超过阈值时，执行扩容
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if (loadFactor() > loadThres) {
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extend()
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}
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val index = hashFunc(key)
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val bucket = buckets[index]
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// 遍历桶，若遇到指定 key ，则更新对应 val 并返回
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for (pair in bucket) {
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if (pair.key == key) {
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pair.value = value
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return
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}
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}
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// 若无该 key ，则将键值对添加至尾部
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val pair = Pair(key, value)
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bucket.add(pair)
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size++
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}
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/* 删除操作 */
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fun remove(key: Int) {
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val index = hashFunc(key)
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val bucket = buckets[index]
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// 遍历桶，从中删除键值对
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for (pair in bucket) {
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if (pair.key == key) {
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bucket.remove(pair)
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size--
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break
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}
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}
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}
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/* 扩容哈希表 */
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fun extend() {
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// 暂存原哈希表
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val bucketsTmp = buckets
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// 初始化扩容后的新哈希表
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capacity *= extendRatio
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// mutablelist 无固定大小
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buckets = mutableListOf()
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for (i in 0..<capacity) {
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buckets.add(mutableListOf())
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}
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size = 0
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// 将键值对从原哈希表搬运至新哈希表
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for (bucket in bucketsTmp) {
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for (pair in bucket) {
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put(pair.key, pair.value)
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}
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}
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}
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/* 打印哈希表 */
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fun print() {
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for (bucket in buckets) {
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val res = mutableListOf<String>()
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for (pair in bucket) {
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val k = pair.key
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val v = pair.value
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res.add("$k -> $v")
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}
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println(res)
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}
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}
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}
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/* Driver Code */
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fun main() {
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/* 初始化哈希表 */
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val map = HashMapChaining()
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/* 添加操作 */
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// 在哈希表中添加键值对 (key, value)
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map.put(12836, "小哈")
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map.put(15937, "小啰")
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map.put(16750, "小算")
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map.put(13276, "小法")
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map.put(10583, "小鸭")
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println("\n添加完成后，哈希表为\nKey -> Value")
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map.print()
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/* 查询操作 */
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// 向哈希表中输入键 key ，得到值 value
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val name = map.get(13276)
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println("\n输入学号 13276 ，查询到姓名 $name")
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/* 删除操作 */
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// 在哈希表中删除键值对 (key, value)
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map.remove(12836)
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println("\n删除 12836 后，哈希表为\nKey -> Value")
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map.print()
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}
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156
codes/kotlin/chapter_hashing/hash_map_open_addressing.kt
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156
codes/kotlin/chapter_hashing/hash_map_open_addressing.kt
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/**
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* File: hash_map_open_addressing.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_hashing
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/* 开放寻址哈希表 */
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class HashMapOpenAddressing {
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private var size: Int = 0 // 键值对数量
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private var capacity = 4 // 哈希表容量
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private val loadThres: Double = 2.0 / 3.0 // 触发扩容的负载因子阈值
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private val extendRatio = 2 // 扩容倍数
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private var buckets: Array<Pair?> // 桶数组
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private val TOMBSTONE = Pair(-1, "-1") // 删除标记
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/* 构造方法 */
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init {
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buckets = arrayOfNulls(capacity)
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}
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/* 哈希函数 */
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fun hashFunc(key: Int): Int {
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return key % capacity
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}
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/* 负载因子 */
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fun loadFactor(): Double {
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return (size / capacity).toDouble()
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}
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/* 搜索 key 对应的桶索引 */
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fun findBucket(key: Int): Int {
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var index = hashFunc(key)
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var firstTombstone = -1
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// 线性探测，当遇到空桶时跳出
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while (buckets[index] != null) {
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// 若遇到 key ，返回对应的桶索引
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if (buckets[index]?.key == key) {
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// 若之前遇到了删除标记，则将键值对移动至该索引处
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if (firstTombstone != -1) {
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buckets[firstTombstone] = buckets[index]
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buckets[index] = TOMBSTONE
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return firstTombstone // 返回移动后的桶索引
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}
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return index // 返回桶索引
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}
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// 记录遇到的首个删除标记
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if (firstTombstone == -1 && buckets[index] == TOMBSTONE) {
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firstTombstone = index
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}
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// 计算桶索引，越过尾部则返回头部
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index = (index + 1) % capacity
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}
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// 若 key 不存在，则返回添加点的索引
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return if (firstTombstone == -1) index else firstTombstone
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}
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/* 查询操作 */
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fun get(key: Int): String? {
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// 搜索 key 对应的桶索引
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val index = findBucket(key)
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// 若找到键值对，则返回对应 val
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if (buckets[index] != null && buckets[index] != TOMBSTONE) {
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return buckets[index]?.value
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}
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// 若键值对不存在，则返回 null
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return null
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}
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/* 添加操作 */
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fun put(key: Int, value: String) {
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// 当负载因子超过阈值时，执行扩容
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if (loadFactor() > loadThres) {
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extend()
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}
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// 搜索 key 对应的桶索引
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val index = findBucket(key)
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// 若找到键值对，则覆盖 val 并返回
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if (buckets[index] != null && buckets[index] != TOMBSTONE) {
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buckets[index]!!.value = value
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return
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}
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// 若键值对不存在，则添加该键值对
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buckets[index] = Pair(key, value)
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size++
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}
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/* 删除操作 */
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||||
fun remove(key: Int) {
|
||||
// 搜索 key 对应的桶索引
|
||||
val index = findBucket(key)
|
||||
// 若找到键值对，则用删除标记覆盖它
|
||||
if (buckets[index] != null && buckets[index] != TOMBSTONE) {
|
||||
buckets[index] = TOMBSTONE
|
||||
size--
|
||||
}
|
||||
}
|
||||
|
||||
/* 扩容哈希表 */
|
||||
fun extend() {
|
||||
// 暂存原哈希表
|
||||
val bucketsTmp = buckets
|
||||
// 初始化扩容后的新哈希表
|
||||
capacity *= extendRatio
|
||||
buckets = arrayOfNulls(capacity)
|
||||
size = 0
|
||||
// 将键值对从原哈希表搬运至新哈希表
|
||||
for (pair in bucketsTmp) {
|
||||
if (pair != null && pair != TOMBSTONE) {
|
||||
put(pair.key, pair.value)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/* 打印哈希表 */
|
||||
fun print() {
|
||||
for (pair in buckets) {
|
||||
if (pair == null) {
|
||||
println("null")
|
||||
} else if (pair == TOMBSTONE) {
|
||||
println("TOMESTOME")
|
||||
} else {
|
||||
println("${pair.key} -> ${pair.value}")
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/* Driver Code */
|
||||
fun main() {
|
||||
// 初始化哈希表
|
||||
val hashmap = HashMapOpenAddressing()
|
||||
|
||||
// 添加操作
|
||||
// 在哈希表中添加键值对 (key, val)
|
||||
hashmap.put(12836, "小哈")
|
||||
hashmap.put(15937, "小啰")
|
||||
hashmap.put(16750, "小算")
|
||||
hashmap.put(13276, "小法")
|
||||
hashmap.put(10583, "小鸭")
|
||||
println("\n添加完成后，哈希表为\nKey -> Value")
|
||||
hashmap.print()
|
||||
|
||||
// 查询操作
|
||||
// 向哈希表中输入键 key ，得到值 val
|
||||
val name = hashmap.get(13276)
|
||||
println("\n输入学号 13276 ，查询到姓名 $name")
|
||||
|
||||
// 删除操作
|
||||
// 在哈希表中删除键值对 (key, val)
|
||||
hashmap.remove(16750)
|
||||
println("\n删除 16750 后，哈希表为\nKey -> Value")
|
||||
hashmap.print()
|
||||
}
|
||||
62
codes/kotlin/chapter_hashing/simple_hash.kt
Normal file
62
codes/kotlin/chapter_hashing/simple_hash.kt
Normal file
|
|
@ -0,0 +1,62 @@
|
|||
/**
|
||||
* File: simple_hash.kt
|
||||
* Created Time: 2024-01-25
|
||||
* Author: curtishd (1023632660@qq.com)
|
||||
*/
|
||||
|
||||
package chapter_hashing
|
||||
|
||||
const val MODULUS = 10_0000_0007
|
||||
|
||||
/* 加法哈希 */
|
||||
fun addHash(key: String): Int {
|
||||
var hash = 0L
|
||||
for (c in key.toCharArray()) {
|
||||
hash = (hash + c.code) % MODULUS
|
||||
}
|
||||
return hash.toInt()
|
||||
}
|
||||
|
||||
/* 乘法哈希 */
|
||||
fun mulHash(key: String): Int {
|
||||
var hash = 0L
|
||||
for (c in key.toCharArray()) {
|
||||
hash = (31 * hash + c.code) % MODULUS
|
||||
}
|
||||
return hash.toInt()
|
||||
}
|
||||
|
||||
/* 异或哈希 */
|
||||
fun xorHash(key: String): Int {
|
||||
var hash = 0
|
||||
for (c in key.toCharArray()) {
|
||||
hash = hash xor c.code
|
||||
}
|
||||
return hash and MODULUS
|
||||
}
|
||||
|
||||
/* 旋转哈希 */
|
||||
fun rotHash(key: String): Int {
|
||||
var hash = 0L
|
||||
for (c in key.toCharArray()) {
|
||||
hash = ((hash shl 4) xor (hash shr 28) xor c.code.toLong()) % MODULUS
|
||||
}
|
||||
return hash.toInt()
|
||||
}
|
||||
|
||||
/* Driver Code */
|
||||
fun main() {
|
||||
val key = "Hello 算法"
|
||||
|
||||
var hash: Int = addHash(key)
|
||||
println("加法哈希值为 $hash")
|
||||
|
||||
hash = mulHash(key)
|
||||
println("乘法哈希值为 $hash")
|
||||
|
||||
hash = xorHash(key)
|
||||
println("异或哈希值为 $hash")
|
||||
|
||||
hash = rotHash(key)
|
||||
println("旋转哈希值为 $hash")
|
||||
}
|
||||
Loading…
Reference in a new issue