705.DesignHashSet.py

"""
    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.
"""
#Difficulty: Easy
#28 / 28 test cases passed.
#Runtime: 324 ms
#Memory Usage: 40.7 MB

#Your runtime beats 30.93 % of python3 submissions.
#Your memory usage beats 9.64 % of python3 submissions.

class MyHashSet:

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.data = [None] * 1000001

    def add(self, key: int) -> None:
        self.data[key] = key

    def remove(self, key: int) -> None:
        self.data[key] = None

    def contains(self, key: int) -> bool:
        """
        Returns true if this set contains the specified element
        """
        return True if self.data[key] or self.data[key] == 0 else False


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