8/17 每日一題(製作一個哈希表)

 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:

Input
["MyHashSet", "add", "add", "contains", "contains", "add", "contains", "remove", "contains"]
[[], [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(1);      // set = [1]
myHashSet.add(2);      // set = [1, 2]
myHashSet.contains(1); // return True
myHashSet.contains(3); // return False, (not found)
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 <= 106
• At most 104 calls will be made to add, remove, and contains.

class MyHashSet:

    def __init__(self):

        self.myset_list=set()

       

    def add(self, key: int) -> None:

        self.myset_list.add(key)

       

       

       

    def remove(self, key: int) -> None:

        if key in self.myset_list:

            self.myset_list.remove(key)

       

       

    def contains(self, key: int) -> bool:

        if key in self.myset_list:

            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)

--------------------------------------參考解答

class MyHashSet:

    def __init__(self):
        self.hashSet = set()
        

    def add(self, key: int) -> None:
        self.hashSet.add(key)

    def remove(self, key: int) -> None:
        if key in self.hashSet:
            self.hashSet.remove(key)
        
    def contains(self, key: int) -> bool:
        if key in self.hashSet:
            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)