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README.md

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.

Related Topics:
Hash Table, Design

Similar Questions:

Solution 1.

// OJ: https://leetcode.com/problems/design-hashset/
// Author: github.com/lzl124631x
// Time: O(1)
// Space: O(1)
class MyHashSet {
private:
    bitset<1000001> bs; 
public:
    MyHashSet() {}
    void add(int key) { bs.set(key); }
    void remove(int key) { bs.reset(key); }
    bool contains(int key) { return bs.test(key); }
};