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 <= 106104 calls will be made to add, remove, and contains.Follow up: Could you solve the problem without using the built-in HashSet library?
#[derive(Default)]
struct MyHashSet {
table: Vec<bool>,
}
impl MyHashSet {
fn new() -> Self {
MyHashSet {
table: vec![false; 1_000_000],
}
}
fn add(&mut self, key: i32) {
self.table[key as usize] = true;
}
fn remove(&mut self, key: i32) {
self.table[key as usize] = false;
}
fn contains(&self, key: i32) -> bool {
self.table[key as usize]
}
}
#[test]
fn test() {
let mut hs = MyHashSet::new();
hs.add(1);
hs.add(2);
assert_eq!(hs.contains(1), true);
assert_eq!(hs.contains(3), false);
hs.add(2);
assert_eq!(hs.contains(2), true);
hs.remove(2);
assert_eq!(hs.contains(2), false);
}