Why is this solution wrong for minimize digitsum in OCT18?

This is my solution:
https://www.codechef.com/viewsolution/21149273
I have tried every possible case and it works but i am still getting WA…is there still any case im missing?

For the case N=7, D=32, does your solution return the pair (1, 9) – i.e. 1 is the result, 9 is the number of steps?

  • Steps 1-6: 7 + 6 x 32 = 199.
  • Steps 7, 8, 9: DigitSum(199) = 19. Then DigitSum(19) = 10. Then DigitSum(10) = 1.

There is another solution that reduces to 1 in 8 steps.

  • Steps 1-3: 7 + 3 x 32 = 103.
  • Step 4: DigitSum(103) = 4.
  • Steps 5-7: 4 + 3 x 32 = 100.
  • Step 8: DigitSum(100) = 1.
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