Answer of question from https://www.hackerrank.com/challenges/append-and-delete/problem

AppendAndDelete.scala

def appendAndDelete(s: String, t: String, k: Int): String = {
    val sLength = s.length
    val tLength = t.length
    val minLength = Math.min(sLength, tLength)
    var done = false
    var index = 0
    while (done == false && index < minLength) {
        if (s(index).equals(t(index)) == false) {
            done = true
        } else {
            index += 1
        }
    }
    val stepCount = (sLength - index) + (tLength - index)
    println(index)
    println(stepCount)
    if (k.equals(stepCount) ||
        ((k - stepCount) > 0 && 0.equals((k - stepCount) % 2)) ||
        k >= stepCount + 2 * index)
        "Yes" else "No"
}