import Foundation
// Function to sort an array containing only 0s and 1s
func sortBinaryArray(_ arr: inout [Int]) {
var left = 0 // Index to track the left side
var right = arr.count - 1 // Index to track the right side
while left < right {
// If the left index is at 0, move it forward
if arr[left] == 0 {
print("left: \(left)")
left += 1
}
// If the right index is at 1, move it backward
else if arr[right] == 1 {
print("right: \(right)")
right -= 1
}
// If left is 1 and right is 0, swap them
else {
arr.swapAt(left, right)
print("swap() left: \(left) right: \(right)")
left += 1
right -= 1
}
}
}
func main() {
// Input: Binary array
var arr: [Int] = [1, 0, 1, 0, 1, 0, 0, 1, 0]
// Sort the binary array
sortBinaryArray(&arr)
// Output the sorted array
print("Sorted array: ", terminator: "")
for num in arr {
print("\(num) ", terminator: "")
}
}
main()
/*
run:
swap() left: 0 right: 8
left: 1
right: 7
swap() left: 2 right: 6
left: 3
swap() left: 4 right: 5
Sorted array: 0 0 0 0 0 1 1 1 1
*/
