Leetcode problem 705 design a hashset implemented in rust

design_hashset_705.rs

struct MyHashSet {
    buckets: Vec<Vec<i32>>,
}



/**
 * `&self` means the method takes an immutable reference.
 * If you need a mutable reference, change it to `&mut self` instead.
 */
impl MyHashSet {
    fn new() -> Self {
        Self {
            buckets: vec![vec![]; 1000],
        }
    }
    
    fn hash(&self,k: i32) -> usize {
        (k as usize) % 1000
    }

     pub fn add(&mut self, key: i32) {
        let bucket_index = self.hash(key);
        if !self.buckets[bucket_index].contains(&key) {
            self.buckets[bucket_index].push(key);
        }
    }

    pub fn remove(&mut self, key: i32) {
        let bucket_index = self.hash(key);
        if let Some(pos) = self.buckets[bucket_index].iter().position(|&x| x == key) {
            self.buckets[bucket_index].remove(pos);
        }
    }

    pub fn contains(&self, key: i32) -> bool {
        let bucket_index = self.hash(key);
        self.buckets[bucket_index].contains(&key)
    }

}

/**
 * Your MyHashSet object will be instantiated and called as such:
 * let obj = MyHashSet::new();
 * obj.add(key);
 * obj.remove(key);
 * let ret_3: bool = obj.contains(key);
 */