705. 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.

In this question we have to design a set data structure, this set can be designed using different data strucrtures but we will design it using vector.

class MyHashSet {
public:

    vector<int> v;

    MyHashSet() 
    {

    }

    void add(int key) 
    {
        bool flag=false;
        for(int i=0;i<v.size();i++)
        {
            if(v[i]==key)
            {
                flag=true;
            }
        }

        if(!flag)
        {
            v.push_back(key);
        }
    }

    void remove(int key) 
    {
        vector<int> :: iterator it;
        it=v.begin();

        for(int i=0;i<v.size();i++)
        {
            if(v[i]==key)
            {
                v.erase(it+i);
            }
        }
    }

    bool contains(int key) 
    {
        bool flag=false;
        for(int x:v)
        {
            if(x==key)
            {
                flag=true;
            }
        }

        return flag;
    }
};