Package g0701_0800.s0705_design_hashset

Class MyHashSet

java.lang.Object
g0701_0800.s0705_design_hashset.MyHashSet
public class MyHashSet extends Object
705 - Design HashSet.

Easy

Design a HashSet without using any built-in hash table libraries.

Implement MyHashSet class:

  • void add(key) Inserts the value key into the HashSet.
  • bool contains(key) Returns whether the value key exists in the HashSet or not.
  • void remove(key) Removes the value key in the HashSet. If key does not exist in the HashSet, do nothing.

Example 1:

Input

 ["MyHashSet", "add", "add", "contains", "contains", "add", "contains", "remove", "contains"]
 [ [], [1], [2], [1], [3], [2], [2], [2], [2]]

Output: [null, null, null, true, false, null, true, null, false]

Explanation:

 MyHashSet myHashSet = new MyHashSet(); 
 myHashSet.add(1); // set = [1] 
 myHashSet.add(2); // set = [1, 2] 
 myHashSet.contains(1); // return True 
 myHashSet.contains(3); // return False, (not found) 
 myHashSet.add(2); // set = [1, 2] 
 myHashSet.contains(2); // return True 
 myHashSet.remove(2); // set = [1] 
 myHashSet.contains(2); // return False, (already removed)

Constraints:

  • 0 <= key <= 106
  • At most 104 calls will be made to add, remove, and contains.

  • Constructor Details

    • MyHashSet

      public MyHashSet()

  • Method Details

    • add

      public void add(int key)

    • remove

      public void remove(int key)

    • contains

      public boolean contains(int key)