[Swift] 순열, 조합

순열

func permutation<T>(array: [T], n: Int) {
    
    var visited = [Bool](repeating: false, count: array.count)
    
    func permutation(current: [T]) {
        if current.count == n {
            print(current)
            return
        }
        
        for i in 0..<array.count {
            if !visited[i] {
                visited[i] = true
                permutation(current: current + [array[i]])
                visited[i] = false
            }
        }
    }
    permutation(current: [])
}

조합

func combination<T>(array: [T], n: Int) {
    
    func combination(index: Int, current: [T]) {
        if current.count == n {
            print(current)
            return
        }
        for i in index..<array.count {
            combination(index: i + 1, current: current + [array[i]])
        }
    }
    combination(index: 0, current: [])
}

 

출처 : let us Go! 만도스님