title: Count Numbers That Dont Contain 3
signature: count_numbers_that_dont_contain_3 <- function(n) {
source_py: def count_numbers_that_dont_contain_3(n):
      if (n < 3):
          return n
      elif ((n >= 3) and (n < 10)):
          return (n - 1)
      po = 1
      while ((n / po) > 9):
          po = (po * 10)
      msd = (n / po)
      if (msd != 3):
          return (((count_numbers_that_dont_contain_3(msd) * count_numbers_that_dont_contain_3((po - 1))) + count_numbers_that_dont_contain_3(msd)) + count_numbers_that_dont_contain_3((n % po)))
      else:
          return count_numbers_that_dont_contain_3(((msd * po) - 1))
source_cpp: int count_numbers_that_dont_contain_3(int n) {
    if ( n < 3 ) return n;
    if ( n >= 3 && n < 10 ) return n - 1;
    int po = 1;
    while ( n / po > 9 ) po = po * 10;
    int msd = n / po;
    if ( msd != 3 ) return count_numbers_that_dont_contain_3 ( msd ) * count_numbers_that_dont_contain_3 ( po - 1 ) + count_numbers_that_dont_contain_3 ( msd ) + count_numbers_that_dont_contain_3 ( n % po );
    else return count_numbers_that_dont_contain_3 ( msd * po - 1 );
  }