mastermind.kt

package mastermind

import kotlin.math.min

data class Evaluation(val rightPosition: Int, val wrongPosition: Int)

fun evaluateGuess(secret: String, guess: String): Evaluation {

    val wp = secret.zip(guess).count { it.first == it.second /*(s, g) -> s == g*/ }

    val common = "ABCDEF".sumBy { c ->
        min(
            secret.count { it == c /*s -> s==c*/ },
            guess.count { it == c /*g -> g == c*/ }
        )
    }
    return Evaluation(wp, common - wp)
}


// ------ MY INITIAL IMPERATIVE SOLUTION  .-< ----------//
fun evalGuess(secret: String, guess: String): Evaluation {

    var rp = 0
    var wp = 0
    val se = secret.toCharArray() // defensive copies
    val ge = guess.toCharArray()

    for ((index, element) in guess.withIndex()) { // find right position first
        if (element == secret[index]) {
            rp += 1
            se[index] = '-'// replace element from secret and guess
            ge[index] = '#'// that do not match
        }
    }

    for ((index, element) in ge.withIndex()) { // find wrong positions
        if (element in se.toList()) {
            wp += 1
            se[se.indexOf(element)] = '@' // same here
            ge[index] = '!'
        }
    }
    return Evaluation(rp, wp)
}

fun main() {
    evalGuess("ABC", "ADC") // 0,1
    // evaluateGuess("ABCD", "EAAA") // 0,1
    // evaluateGuess("BDAD", "AAAE") // 1,0
    // evalGuess("ABC", "CAA") // 1,0

}