# Design Hashset Problem

## Description

LeetCode Problem 705.

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:

``````1
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Input
[[], [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(2);      // set = [1, 2]
myHashSet.contains(1); // return True
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 <= 10^6
• At most 10^4 calls will be made to add, remove, and contains.

## Sample C++ Code

``````1
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class MyHashSet {
public:
/** Initialize your data structure here. */
int ht[1000000] = {0};

MyHashSet() {

}

ht[key] = 1;
}

void remove(int key) {
ht[key] = 0;
}

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

/**
* Your MyHashSet object will be instantiated and called as such:
* MyHashSet* obj = new MyHashSet();
* obj->remove(key);
* bool param_3 = obj->contains(key);
*/
``````