CODEWITHSUNDEEP
scalafunctionfunctional-programming
Unknown8628
Unknown8628

Reputation: 11

Find the N happy number in Scala

Hi everyone I have been working on this problem which is to find the n-th happy number. But I am struggling to make it work here as it is showing

Found: Unit

Required: Int

Maybe you are missing an else part for the conditional?

Here is how it works:

nThHappy(1) returns 1

• nThHappy(3) returns 10

• nThHappy(11) returns 49

• nThHappy(19) returns 97

def nThHappy(k: Int): Int = {
   def isHappy(n: Int): Boolean = {
     def sumOfDigitsSquared(n: Int): Int = n.toString.foldLeft(0) { (product, num) => product + num.asDigit * num.asDigit }

     def loop(seen: Set[Int], x: Int): Boolean = {
       x match {
         case 1 => true
         case _ if seen.contains(x) => false
         case _ => loop(seen + x, sumOfDigitsSquared(x))
       }
     }
     loop(Set(),n)
   }
   def helper(countN: Int,countK: Int, hNum:Int): Int =
     countK match {
     case hNum => countN
     case _ => {
       if (isHappy(countN) == false) {
         helper(countN+1, countK, hNum)
       }
     else if(isHappy(countN) == true) { // <-- Here is the problem
         helper(countN+1, countK+1, hNum)
       }

     }
   }
   helper(0,0,k)
 }

Upvotes: 0

Views: 114

Answers (1)

Tim
Tim

Reputation: 27421

You need an else part for that last if, or just remove the test (which is pointless), or just use match:

 case _ if isHappy(countN) =>
     helper(countN+1, countK+1, hNum)
 case _ =>
     helper(countN+1, countK, hNum)

Upvotes: 1

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