Package g0701_0800.s0706_design_hashmap

Class MyHashMap

java.lang.Object

g0701_0800.s0706_design_hashmap.MyHashMap

public class MyHashMap
extends Object

706 - Design HashMap.<p>Easy</p> <p>Design a HashMap without using any built-in hash table libraries.</p> <p>Implement the <code>MyHashMap</code> class:</p> <ul> <li><code>MyHashMap()</code> initializes the object with an empty map.</li> <li><code>void put(int key, int value)</code> inserts a <code>(key, value)</code> pair into the HashMap. If the <code>key</code> already exists in the map, update the corresponding <code>value</code>.</li> <li><code>int get(int key)</code> returns the <code>value</code> to which the specified <code>key</code> is mapped, or <code>-1</code> if this map contains no mapping for the <code>key</code>.</li> <li><code>void remove(key)</code> removes the <code>key</code> and its corresponding <code>value</code> if the map contains the mapping for the <code>key</code>.</li> </ul> <p><strong>Example 1:</strong></p> <p><strong>Input</strong></p> <p>[&ldquo;MyHashMap&rdquo;, &ldquo;put&rdquo;, &ldquo;put&rdquo;, &ldquo;get&rdquo;, &ldquo;get&rdquo;, &ldquo;put&rdquo;, &ldquo;get&rdquo;, &ldquo;remove&rdquo;, &ldquo;get&rdquo;]</p> <p>[ [], [1, 1], [2, 2], [1], [3], [2, 1], [2], [2], [2]]</p> <p><strong>Output:</strong> [null, null, null, 1, -1, null, 1, null, -1]</p> <p><strong>Explanation:</strong></p> <pre><code> MyHashMap myHashMap = new MyHashMap(); myHashMap.put(1, 1); // The map is now [[1,1]] myHashMap.put(2, 2); // The map is now [[1,1], [2,2]] myHashMap.get(1); // return 1, The map is now [[1,1], [2,2]] myHashMap.get(3); // return -1 (i.e., not found), The map is now [[1,1], [2,2]] myHashMap.put(2, 1); // The map is now [[1,1], [2,1]] (i.e., update the existing value) myHashMap.get(2); // return 1, The map is now [[1,1], [2,1]] myHashMap.remove(2); // remove the mapping for 2, The map is now [[1,1]] myHashMap.get(2); // return -1 (i.e., not found), The map is now [[1,1]] </code></pre> <p><strong>Constraints:</strong></p> <ul> <li><code>0 <= key, value <= 10⁶</code></li> <li>At most <code>10⁴</code> calls will be made to <code>put</code>, <code>get</code>, and <code>remove</code>.</li> </ul>

Constructor Summary

Constructors

Constructor	Description
MyHashMap()

Method Summary

Modifier and Type	Method	Description
int	get(int key)
void	put(int key, int value)
void	remove(int key)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MyHashMap

public MyHashMap()

Method Details

put

public void put(int key,
 int value)

get

public int get(int key)

remove

public void remove(int key)