Recursive Digit Sum

  • + 1 comment

    For mine, I started out by making the string super long. Instead, I should have multiplied the sum by "k". Making the string super long would take way too long, which was why it didn't work.

    • + 0 comments

      superDigit(repeat k times of number_n) = superDigit( k * superDigit(number_n))

      public static int superDigitHelper(String n) {
          int sum = 0;
          for(int i=0; i<n.length();i++){
            sum += Character.getNumericValue(n.charAt(i));
          }
          if(sum>=10){
              sum = superDigitHelper(String.valueOf(sum));
          }
          return sum;
      }
      public static int superDigit(String n, int k) {
          // Write your code here
          int superDigitN = superDigitHelper(n);
          int p = superDigitN*k;
          return superDigitHelper(String.valueOf(p));
      }