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### by Sumit Chourasia | Sep 29, 2020 | Category :coding | Tags : algorithmडेटा-संरचनाआसानhash-tableleetcode

#### 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.contains(1);    // returns true
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];
}

if(Contains(key)){
return;
}
int hash = GetHash(key);
if(table[hash] == null){
table[hash]=new List<int>();
}
}

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.Remove(key);
* bool param_3 = obj.Contains(key);
*/``````

Time Complexity: O(1) Amortised time complexity

Space Complexity: O(n)

Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia