705. Design HashSet #

Problem #

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.

Problem Summary #

Design a hash set without using any built-in hash table libraries. Specifically, your design should include the following functions:

• add(value): Insert a value into the hash set.
• contains(value): Return whether this value exists in the hash set.
• remove(value): Remove the given value from the hash set. If this value does not exist in the hash set, do nothing.

Note:

• All values are in the range [1, 1000000].
• The total number of operations is in the range [1, 10000].
• Do not use the built-in hash set library.

Solution Ideas #

• Easy problem. Design a hashset data structure that requires these 3 methods: add(value), contains(value), and remove(value).

Code #

package leetcode

type MyHashSet struct {
	data []bool
}

/** Initialize your data structure here. */
func Constructor705() MyHashSet {
	return MyHashSet{
		data: make([]bool, 1000001),
	}
}

func (this *MyHashSet) Add(key int) {
	this.data[key] = true
}

func (this *MyHashSet) Remove(key int) {
	this.data[key] = false
}

/** Returns true if this set contains the specified element */
func (this *MyHashSet) Contains(key int) bool {
	return this.data[key]
}

/**
 * Your MyHashSet object will be instantiated and called as such:
 * obj := Constructor();
 * obj.Add(key);
 * obj.Remove(key);
 * param_3 := obj.Contains(key);
 */