PutZerosToTheEnd.swift

//
//  PutZerosToTheEnd.swift
//  Test
//
//  Created by KONSTANTIN KUSAINOV on 16/12/2018.
//  Copyright © 2018 KONSTANTIN KUSAINOV. All rights reserved.
//

import Foundation

struct PutZerosToTheEnd {
    static func test() {
        var arr = [1, 9, 0, 0, 0, 14]
        print("PutZerosToTheEnd = \(arr)")
        transform(arr: &arr)
        print("PutZerosToTheEnd: \(arr)")
        
        arr = [0, 10, 9, 0, 0, 0, 14, 5]
        print("=== PutZerosToTheEnd ===")
        print("PutZerosToTheEnd = \(arr)")
        transform(arr: &arr)
        print("PutZerosToTheEnd: \(arr)")
    }
    
    static private func transform(arr: inout [Int]) {
        let n = arr.count
        
        var j = (n - 1)
        for i in (0...j).reversed() {
            let val_i = arr[i]
            
            if val_i == 0 {
                self.swapKK(arr: &arr, lhsIndex: i, rhsIndex: j)
                j -= 1
            }
            
        }
    }
    
    static func swapKK(arr: inout Array<Int>, lhsIndex: Int, rhsIndex: Int ) {
        let lhs = arr[lhsIndex]
        arr[lhsIndex] = arr[rhsIndex]
        arr[rhsIndex] = lhs
    }
}