Can you give examples of collision resolution methods when working with hash tables?

Hash collisions occur when different keys hash to the same cell in a hash table. The main methods to resolve collisions are:

1. Chaining method — each cell in the hash table stores a linked list of elements that have hashed to that cell. When a collision occurs, the new element is added to the list.

2. Open addressing — upon collision, the next free cell is sought according to a specific rule (linear probing, quadratic probing, double hashing).

Example of chaining method:

class HashTable {
    var buckets: [[(key: String, value: Int)]]
    
    init(size: Int) {
        buckets = Array(repeating: [], count: size)
    }
    
    func hash(_ key: String) -> Int {
        return abs(key.hashValue) % buckets.count
    }
    
    func insert(key: String, value: Int) {
        let index = hash(key)
        buckets[index].append((key, value))
    }
}

Thus, the choice of method depends on performance and memory requirements.