Given a non-negative number represented as an array of digits,

add 1 to the number ( increment the number represented by the digits ).

The digits are stored such that the most significant digit is at the head of the list. There can be upto 10,000 digits in the input array.

Example:

If the vector has [1, 2, 3]

the returned vector should be [1, 2, 4]

as 123 + 1 = 124.

def plusOne(a)
        new_number = a.join.to_i + 1
        result = []
        while new_number > 0
            result.push new_number%10
            new_number /= 10
        end
        result.reverse
 end

def plusOne(a)
      carry = 1
      start_index = a.size - 1
      temp_result = []
      ans = []

      for i in start_index.downto(0)
            sum = a[i] + carry
            carry = sum/10
            temp_result.push sum%10
      end
      temp_result.push carry

      start_index = temp_result.size - 1
      while start_index >= 0 and temp_result[start_index] == 0
          start_index -= 1
      end

      while start_index >= 0
          ans.push temp_result[start_index]
          start_index -= 1
      end
      ans
    end