126 lines
3.0 KiB
Kotlin
126 lines
3.0 KiB
Kotlin
/**
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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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/* Key-value pair */
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class Pair(
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var key: Int,
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var _val: String
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)
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/* Hash table based on array implementation */
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class ArrayHashMap {
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// Initialize an array, containing 100 buckets
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private val buckets = arrayOfNulls<Pair>(100)
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/* Hash function */
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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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/* Query operation */
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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._val
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}
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/* Add operation */
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fun put(key: Int, _val: String) {
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val pair = Pair(key, _val)
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val index = hashFunc(key)
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buckets[index] = pair
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}
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/* Remove operation */
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fun remove(key: Int) {
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val index = hashFunc(key)
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// Set to null, indicating removal
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buckets[index] = null
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}
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/* Get all key-value pairs */
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fun pairSet(): MutableList<Pair> {
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val pairSet = mutableListOf<Pair>()
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for (pair in buckets) {
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if (pair != null)
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pairSet.add(pair)
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}
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return pairSet
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}
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/* Get all keys */
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fun keySet(): MutableList<Int> {
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val keySet = mutableListOf<Int>()
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for (pair in buckets) {
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if (pair != null)
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keySet.add(pair.key)
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}
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return keySet
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}
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/* Get all values */
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fun valueSet(): MutableList<String> {
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val valueSet = mutableListOf<String>()
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for (pair in buckets) {
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if (pair != null)
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valueSet.add(pair._val)
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}
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return valueSet
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}
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/* Print hash table */
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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 _val = kv._val
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println("$key -> $_val")
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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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/* Initialize hash table */
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val map = ArrayHashMap()
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/* Add operation */
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// Add key-value pair (key, value) to the hash table
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map.put(12836, "Ha")
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map.put(15937, "Luo")
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map.put(16750, "Suan")
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map.put(13276, "Fa")
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map.put(10583, "Ya")
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println("\nAfter adding, the hash table is\nKey -> Value")
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map.print()
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/* Query operation */
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// Enter key to the hash table, get value
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val name = map.get(15937)
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println("\nInput student ID 15937, found name $name")
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/* Remove operation */
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// Remove key-value pair (key, value) from the hash table
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map.remove(10583)
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println("\nAfter removing 10583, the hash table is\nKey -> Value")
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map.print()
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/* Traverse hash table */
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println("\nTraverse key-value pairs Key -> Value")
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for (kv in map.pairSet()) {
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println("${kv.key} -> ${kv._val}")
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}
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println("\nIndividually traverse keys 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("\nIndividually traverse values Value")
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for (_val in map.valueSet()) {
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println(_val)
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}
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} |