design-hashset.py

 # ~ Design HashSet
 # ~ 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.

class MyHashSet:

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.list = {}
        
        

    def add(self, key: int) -> None:
        
        if key not in self.list.keys():
            self.list[key] = 1
        else:
            self.list[key] += 1

    def remove(self, key: int) -> None:
        if key in self.list.keys():
            del self.list[key]
        

    def contains(self, key: int) -> bool:
        """
        Returns true if this set contains the specified element
        """
        if key not in self.list.keys():
            return False
        else:
            return True
        


# Your MyHashSet object will be instantiated and called as such:
# obj = MyHashSet()
# obj.add(key)
# obj.remove(key)
# param_3 = obj.contains(key)