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
2026-07-12 07:26:07 +00:00 · 2024-03-12 14:08:15 +08:00
parent cf0817370b
commit eadf4c86d4
6 changed files with 579 additions and 0 deletions
@@ -0,0 +1,130 @@
+/**
+ * File: array_hash_map.kt
+ * Created Time: 2024-01-25
+ * Author: curtishd (1023632660@qq.com)
+ */
+
+package chapter_hashing
+
+/* 键值对 */
+class Pair(
+    var key: Int,
+    var value: String
+)
+
+/* 基于数组实现的哈希表 */
+class ArrayHashMap {
+    private val buckets = arrayOfNulls<Pair>(100)
+
+    /* 构造方法 */
+    init {
+        // 初始化数组，包含 100 个桶
+        for (i in 0..<100) {
+            buckets[i] = null
+        }
+    }
+
+    /* 哈希函数 */
+    fun hashFunc(key: Int): Int {
+        val index = key % 100
+        return index
+    }
+
+    /* 查询操作 */
+    fun get(key: Int): String? {
+        val index = hashFunc(key)
+        val pair = buckets[index] ?: return null
+        return pair.value
+    }
+
+    /* 添加操作 */
+    fun put(key: Int, value: String) {
+        val pair = Pair(key, value)
+        val index = hashFunc(key)
+        buckets[index] = pair
+    }
+
+    /* 删除操作 */
+    fun remove(key: Int) {
+        val index = hashFunc(key)
+        // 置为 null ，代表删除
+        buckets[index] = null
+    }
+
+    /* 获取所有键值对 */
+    fun pairSet(): MutableList<Pair> {
+        val pairSet = ArrayList<Pair>()
+        for (pair in buckets) {
+            if (pair != null) pairSet.add(pair)
+        }
+        return pairSet
+    }
+
+    /* 获取所有键 */
+    fun keySet(): MutableList<Int> {
+        val keySet = ArrayList<Int>()
+        for (pair in buckets) {
+            if (pair != null) keySet.add(pair.key)
+        }
+        return keySet
+    }
+
+    /* 获取所有值 */
+    fun valueSet(): MutableList<String> {
+        val valueSet = ArrayList<String>()
+        for (pair in buckets) {
+            pair?.let { valueSet.add(it.value) }
+        }
+        return valueSet
+    }
+
+    /* 打印哈希表 */
+    fun print() {
+        for (kv in pairSet()) {
+            val key = kv.key
+            val value = kv.value
+            println("${key}->${value}")
+        }
+    }
+}
+
+/* Driver Code */
+fun main() {
+    /* 初始化哈希表 */
+    val map = ArrayHashMap()
+
+    /* 添加操作 */
+    // 在哈希表中添加键值对 (key, value)
+    map.put(12836, "小哈")
+    map.put(15937, "小啰")
+    map.put(16750, "小算")
+    map.put(13276, "小法")
+    map.put(10583, "小鸭")
+    println("\n添加完成后，哈希表为\nKey -> Value")
+    map.print()
+
+    /* 查询操作 */
+    // 向哈希表中输入键 key ，得到值 value
+    val name: String? = map.get(15937)
+    println("\n输入学号 15937 ，查询到姓名 $name")
+
+    /* 删除操作 */
+    // 在哈希表中删除键值对 (key, value)
+    map.remove(10583)
+    println("\n删除 10583 后，哈希表为\nKey -> Value")
+    map.print()
+
+    /* 遍历哈希表 */
+    println("\n遍历键值对 Key->Value")
+    for (kv in map.pairSet()) {
+        println("${kv.key} -> ${kv.value}")
+    }
+    println("\n单独遍历键 Key")
+    for (key in map.keySet()) {
+        println(key)
+    }
+    println("\n单独遍历值 Value")
+    for (value in map.valueSet()) {
+        println(value)
+    }
+}