get the prime factors

prime_factors.swift

func primeFactor(n: Int) -> [Int] {
    
    var i: Int = 2
    var A: [Int] = Array(repeating: 0, count: n - 1)
    var result: [Int] = []
    
    while i < n/2 {
    
        var counter: Int = 0
        var index: Int = i * i + i * counter - 2
        
        while index < n - 1 {

            if A[index] == 0 { A[index] = i }
            
            if index == n - 2 { A[index] = i }

            counter = counter + 1
            index = i * i + i * counter - 2
        }
    
        i = i + 1
    }
    
    var finished: Bool = false
    var index = n - 2

    while !finished {

        if A[index] == 0 {

            result.append(index + 2); finished = true
        } else {

            result.append(A[index])
            index = (index + 2) / A[index] - 2
        }
    }
    
    return result
    
}

let dd = primeFactor(n: 35)