Package g0701_0800.s0705_design_hashset

Class 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 Detail

      • MyHashSet

        public MyHashSet()

    • Method Detail

      • add

        public void add​(int key)

      • remove

        public void remove​(int key)

      • contains

        public boolean contains​(int key)