705. Design HashSet LeetCode Solution

In this guide, you will get 705. Design HashSet LeetCode Solution with the best time and space complexity. The solution to Design HashSet problem is provided in various programming languages like C++, Java, and Python. This will be helpful for you if you are preparing for placements, hackathons, interviews, or practice purposes. The solutions provided here are very easy to follow and include detailed explanations.

Table of Contents

1. Problem Statement
2. Complexity Analysis
3. Design HashSet solution in C++
4. Design HashSet solution in Java
5. Design HashSet solution in Python
6. Additional Resources

Problem Statement of Design HashSet

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.

Complexity Analysis

• Time Complexity: O(1)
• Space Complexity: O(n)

705. Design HashSet LeetCode Solution in C++

class MyHashSet {
 public:
  /** Initialize your data structure here. */
  MyHashSet() : set(1000001) {}

  void add(int key) {
    set[key] = true;
  }

  void remove(int key) {
    set[key] = false;
  }

  /** Returns true if this set contains the specified element */
  bool contains(int key) {
    return set[key];
  }

 private:
  vector<bool> set;
};
/* code provided by PROGIEZ */

705. Design HashSet LeetCode Solution in Java

class MyHashSet {
  /** Initialize your data structure here. */
  public MyHashSet() {
    set = new boolean[1000001];
  }

  public void add(int key) {
    set[key] = true;
  }

  public void remove(int key) {
    set[key] = false;
  }

  /** Returns true if this set contains the specified element */
  public boolean contains(int key) {
    return set[key];
  }

  private boolean[] set = new boolean[1000001];
}
// code provided by PROGIEZ

705. Design HashSet LeetCode Solution in Python

class MyHashSet:
  def __init__(self):
    self.set = [False] * 1000001

  def add(self, key: int) -> None:
    self.set[key] = True

  def remove(self, key: int) -> None:
    self.set[key] = False

  def contains(self, key: int) -> bool:
    return self.set[key]
 # code by PROGIEZ

Additional Resources

• Explore all LeetCode problem solutions at Progiez here
• Explore all problems on LeetCode website here

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