For loop with multiple non-nested counters in scala

Question

I have this code snippet in java

int[] arrA = ...;
int[] arrB = ...;
int n = ...;
boolean isPermuting = true;
for(int i = 0, j = arrB.length - 1; i < n; i++, j--) {
   if(arrA[i] + arrB[j] < k) {
      isPermuting = false;
      break;
   }
}

I know there is a way to put multiple counters in the same for loop in scala but the end up being nested. For example:

for(i <- 1 to 10 ; j <- 10 to 20) // in scala

is the same as

for(int i = 1; i <= 10 ; i ++){
   for(int j = 10; j <= 20; j++){ // in java

but I don't know how to do this for non nested counters

locorecto · Accepted Answer · 2019-07-31 17:34:32Z

1

I don't know if there is a way to do with for loops in scala inline but you can use while loops and change the organization a bit. Make sure you import Breaks from utils.

 import scala.util.control.Breaks._

  var n = 4
  var k = 3
  val arrA : Array[Int] = Array(8, 2, 3, 4, 5)
  val arrB : Array[Int] = Array(5, 4, 3, 2, 6)
  var isPermuting: Boolean = true
  var i: Int = 0
  var j: Int = arrB.length - 1
  breakable {
    while (i < n) {
      if (arrA(i) + arrB(j) < k) {
        isPermuting = false
        break
      }

      i += 1
      j -= 1
    }
  }

  print(isPermuting)

EDIT: This might not be the cleanest way to do it but coming from java is easy enough to understand. I hope it helps

edited Jul 31, 2019 at 17:34

answered Mar 19, 2017 at 1:59

locorecto

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3 Comments

locorecto Over a year ago

added the Breaks implicits in order to make the code work.

pedrofurla Over a year ago

Still not right. For example, I can tell you that the value of i and j by the end of the execution will be 0 and arrB.length - 1.

locorecto Over a year ago

Not the point of the what the OP is asking. He wants to know how to have two different counters in one loop. That's it. Also just added possible values to show how to I will get i to be arrB.lenght -1 and j to be 0 at the end of the execution.

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