This is the 4th day of my participation in the August More Text Challenge

describe

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)
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Note:

0 <= key <= 10^6
At most 104 calls will be made to add, remove, and contains.
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parsing

Implement a Hashset using a list of operations. This method uses built-in functions and is not recommended.

answer

class MyHashSet(object):

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.l = []
    def add(self, key):
        """
        :type key: int
        :rtype: None
        """
        if key not in self.l:
            self.l.append(key)

    def remove(self, key):
        """
        :type key: int
        :rtype: None
        """
        if key in self.l:
            self.l.remove(key)
        
    def contains(self, key):
        """
        Returns true if this set contains the specified element
        :type key: int
        :rtype: bool
        """
        if key in self.l:
            return True
        return False



        	      
		
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The results

Given in the Python online submissions. Memory Usage: 10000 ms Submissions in the Python online list for Design HashSet.Copy the code

parsing

Set the length of the array to 1000001. Set all values to False. If there are any numbers, set the value to True.

answer

class MyHashSet(object):

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.set = [False] * 1000001
    def add(self, key):
        """
        :type key: int
        :rtype: None
        """
        self.set[key] = True

    def remove(self, key):
        """
        :type key: int
        :rtype: None
        """
        self.set[key] = False
        
    def contains(self, key):
        """
        Returns true if this set contains the specified element
        :type key: int
        :rtype: bool
        """
        return self.set[key]
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The results

Given in the Python online submissions. Memory Usage: Submissions in Python online submissions for Design HashSet.Copy the code

Original link: leetcode.com/problems/de…

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