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Design HashSet - Hash Table - Easy - LeetCode - MiniTV

Design HashSet - Hash Table - Easy - LeetCode - मिनी टीवी

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

To be specific, your design should include these functions:

add(value): Insert a value into the HashSet. 
contains(value) : Return whether the value exists in the HashSet or not.
remove(value): Remove a value in the HashSet. If the value does not exist in the HashSet, do nothing.

Example:

MyHashSet hashSet = new MyHashSet();
hashSet.add(1);         
hashSet.add(2);         
hashSet.contains(1);    // returns true
hashSet.contains(3);    // returns false (not found)
hashSet.add(2);          
hashSet.contains(2);    // returns true
hashSet.remove(2);          
hashSet.contains(2);    // returns false (already removed)

Note:

All values will be in the range of [0, 1000000].
The number of operations will be in the range of [1, 10000].
Please do not use the built-in HashSet library.

public class MyHashSet {

    List<int>[] table;
    const int size = 10000;
    /** Initialize your data structure here. */
    public MyHashSet() {
        table = new List<int>[size];
    }
    
    public void Add(int key) {
        if(Contains(key)){
            return;
        }
        int hash = GetHash(key);
        if(table[hash] == null){
            table[hash]=new List<int>();            
        }
        table[hash].Add(key);
    }
    
    public void Remove(int key) {
        int hash = GetHash(key);
        if(table[hash]==null){
            return;
        }
        table[hash].Remove(key);
    }
    
    /** Returns true if this set contains the specified element */
    public bool Contains(int key) {
        int hash = GetHash(key);
        if(table[hash]==null){
            return false;
        }
        
        return table[hash].Contains(key);
    }
    
    private int GetHash(int key){
        return (key * 7)%size;
    }
}

/**
 * Your MyHashSet object will be instantiated and called as such:
 * MyHashSet obj = new MyHashSet();
 * obj.Add(key);
 * obj.Remove(key);
 * bool param_3 = obj.Contains(key);
 */

 


Time Complexity: O(1) Amortised time complexity

Space Complexity: O(n)