Leetcode 705. 设计哈希集合

1.题目基本信息

1.1.题目描述

不使用任何内建的哈希表库设计一个哈希集合（HashSet）。

实现 MyHashSet 类：

• void add(key) 向哈希集合中插入值 key 。

• bool contains(key) 返回哈希集合中是否存在这个值 key 。

• void remove(key) 将给定值 key 从哈希集合中删除。如果哈希集合中没有这个值，什么也不做。

1.2.题目地址

https://leetcode.cn/problems/design-hashset/description/

2.解题方法

2.1.解题思路

链地址法构建哈希集合

3.解题代码

python代码

class Node():
    def __init__(self, val:int = None, next = None):
        self.val = val
        self.next = next

class MyHashSet:
    # 思路：链地址法
    def __init__(self):
        self.base = 1006
        self.arr = []
        for i in range(self.base):
            node = Node()
            self.arr.append([node, node])

    def add(self, key: int) -> None:
        if self.contains(key):
            return
        val = key % self.base
        _, tail = self.arr[val]
        tail.next = Node(val = key)
        self.arr[val][1] = tail.next

    def remove(self, key: int) -> None:
        if not self.contains(key):
            return None
        val = key % self.base
        head, _ = self.arr[val]
        while head.next is not None:
            if head.next.val == key:
                head.next = head.next.next
            else:
                head = head.next
        self.arr[val][1] = head

    def contains(self, key: int) -> bool:
        val = key % self.base
        head, _ = self.arr[val]
        head = head.next
        while head is not None:
            if head.val == key:
                return True
            head = head.next
        return False


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

4.执行结果