Solution.cpp

class MyHashSet {
    struct Entry {
        int value;
        Entry* next;
    };
    
    Entry** buckets;
    int capacity;
    
    std::hash<int> hasher;
    
    void removeNode(Entry** node) {
        Entry* next = (*node)->next;
        Entry* danglingNode = *node;
        *node = next;
        delete danglingNode;
    }
public:
    /** Initialize your data structure here. */
    MyHashSet() {
        buckets = new Entry*[64] {nullptr};
        capacity = 64;
    }
    
    void add(int key) {
        Entry** bucket = &buckets[hasher(key) % capacity];
        while (*bucket != nullptr) {
            if ((*bucket)->value == key) { return; }
            
            bucket = & (*bucket)->next;
        }
        *bucket = new Entry{key, nullptr};
    }
    
    void remove(int key) {
        Entry** bucket = &buckets[hasher(key) % capacity];
        while (*bucket != nullptr) {
            if ((*bucket)->value == key) {
                return removeNode(bucket);
            }
            
            bucket = & (*bucket)->next;
        }
    }
    
    /** Returns true if this set contains the specified element */
    bool contains(int key) {
        Entry** bucket = &buckets[hasher(key) % capacity];
        while (*bucket != nullptr) {
            if ((*bucket)->value == key) { return true; }
            
            bucket = & (*bucket)->next;
        }
        return false;
    }
};