Maximum and minimum sums from two numbers with digit replacements

DS_ALGO_Strings_003.kt

import kotlin.system.*
import kotlin.contracts.*
import java.util.*

fun main() {
    
    fun printMinAndMax(x1: Int, x2: Int, maxDigit: Int, minDigit: Int){
        val s1 = x1.toString()
        val s2 = x2.toString()
        
        if(minDigit >= maxDigit){
            println("minDigit cannot be grater than or equal to maxDigit.")
            return
        }
        
        val maxCA = maxDigit.toString().toCharArray()
        val minCA = minDigit.toString().toCharArray()
        
        if(minCA.size > 1 || maxCA.size > 1){
            println("Please provide single digit values for maxDigit and minDigit.")
            return 
        }
        
        val minC = minCA[0]
        val maxC = maxCA[0]
        
        
        if((!s1.contains(minC) && !s1.contains(maxC)) || (!s2.contains(minC) && !s2.contains(maxC))) {
            println("Provided numbers do not contain $minC or ${maxC}")
            return
        }
        
        
        fun printMin(){
            val c1 = s1.toCharArray()
            val c2 = s2.toCharArray()

            for(i in 0 until c1.size){
                if(c1[i] == maxC){
                    c1[i] = minC
                }
            }
            
            for(i in 0 until c2.size){
                if(c2[i] == maxC){
                    c2[i] = minC
                }
            }

            
            println("Min sum: ${String(c1).toInt() + String(c2).toInt()}")
        }
        
        fun printMax(){
            val c1 = s1.toCharArray()
            val c2 = s2.toCharArray()

            for(i in 0 until c1.size){
                if(c1[i] == minC){
                    c1[i] = maxC
                }
            }

            for(i in 0 until c2.size){
                if(c2[i] == minC){
                    c2[i] = maxC
                }
            }

            println("Max sum: ${String(c1).toInt() + String(c2).toInt()}")
        }
        
        printMin()
        printMax()
    }
    
    printMinAndMax(745, 777, 7, 5)
}