135 lines
3.5 KiB
C#
135 lines
3.5 KiB
C#
/**
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* File: array_hash_map.cs
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* Created Time: 2022-12-23
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* Author: haptear (haptear@hotmail.com)
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*/
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namespace hello_algo.chapter_hashing;
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/* Key-value pair int->string */
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class Pair(int key, string val) {
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public int key = key;
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public string val = val;
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}
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/* Hash table based on array implementation */
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class ArrayHashMap {
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List<Pair?> buckets;
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public ArrayHashMap() {
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// Initialize an array, containing 100 buckets
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buckets = [];
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for (int i = 0; i < 100; i++) {
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buckets.Add(null);
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}
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}
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/* Hash function */
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int HashFunc(int key) {
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int index = key % 100;
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return index;
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}
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/* Query operation */
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public string? Get(int key) {
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int index = HashFunc(key);
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Pair? pair = buckets[index];
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if (pair == null) return null;
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return pair.val;
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}
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/* Add operation */
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public void Put(int key, string val) {
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Pair pair = new(key, val);
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int index = HashFunc(key);
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buckets[index] = pair;
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}
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/* Remove operation */
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public void Remove(int key) {
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int 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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public List<Pair> PairSet() {
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List<Pair> pairSet = [];
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foreach (Pair? 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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public List<int> KeySet() {
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List<int> keySet = [];
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foreach (Pair? 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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public List<string> ValueSet() {
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List<string> valueSet = [];
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foreach (Pair? 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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public void Print() {
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foreach (Pair kv in PairSet()) {
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Console.WriteLine(kv.key + " -> " + kv.val);
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}
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}
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}
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public class array_hash_map {
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[Test]
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public void Test() {
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/* Initialize hash table */
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ArrayHashMap map = new();
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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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Console.WriteLine("\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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string? name = map.Get(15937);
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Console.WriteLine("\nEnter 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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Console.WriteLine("\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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Console.WriteLine("\nTraverse key-value pairs Key->Value");
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foreach (Pair kv in map.PairSet()) {
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Console.WriteLine(kv.key + " -> " + kv.val);
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}
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Console.WriteLine("\nIndividually traverse keys Key");
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foreach (int key in map.KeySet()) {
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Console.WriteLine(key);
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}
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Console.WriteLine("\nIndividually traverse values Value");
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foreach (string val in map.ValueSet()) {
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Console.WriteLine(val);
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}
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}
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}
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