How do I implement DFS and BFS in Swift?

import Foundation

class Graph {
    var adjList: [Int: [Int]] = [:]
    
    func addEdge(from source: Int, to destination: Int) {
        if adjList[source] != nil {
            adjList[source]?.append(destination)
        } else {
            adjList[source] = [destination]
        }
        
        // For undirected graph (if needed)
        if adjList[destination] != nil {
            adjList[destination]?.append(source)
        } else {
            adjList[destination] = [source]
        }
    }
    
    // Depth First Search
    func dfs(start: Int) {
        var visited = Set()
        dfsHelper(node: start, visited: &visited)
    }
    
    private func dfsHelper(node: Int, visited: inout Set) {
        visited.insert(node)
        print(node)
        
        guard let neighbors = adjList[node] else { return }
        for neighbor in neighbors {
            if !visited.contains(neighbor) {
                dfsHelper(node: neighbor, visited: &visited)
            }
        }
    }
    
    // Breadth First Search
    func bfs(start: Int) {
        var visited = Set()
        var queue: [Int] = [start]
        visited.insert(start)
        
        while !queue.isEmpty {
            let node = queue.removeFirst()
            print(node)
            
            guard let neighbors = adjList[node] else { continue }
            for neighbor in neighbors {
                if !visited.contains(neighbor) {
                    visited.insert(neighbor)
                    queue.append(neighbor)
                }
            }
        }
    }
}

// Example of usage
let graph = Graph()
graph.addEdge(from: 1, to: 2)
graph.addEdge(from: 1, to: 3)
graph.addEdge(from: 2, to: 4)
graph.addEdge(from: 3, to: 5)

print("DFS:")
graph.dfs(start: 1)

print("BFS:")
graph.bfs(start: 1)