Add One To Number

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.

Example:

If the vector has [1, 2, 3]

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

as 123 + 1 = 124.

NOTE: Certain things are intentionally left unclear in this question which you should practice asking the interviewer.
For example, for this problem, following are some good questions to ask :

  • Q : Can the input have 0’s before the most significant digit. Or in other words, is 0 1 2 3 a valid input?
  • A : For the purpose of this question, YES

  • Q : Can the output have 0’s before the most significant digit? Or in other words, is 0 1 2 4 a valid output?
  • A : For the purpose of this question, NO. Even if the input has zeroes before the most significant digit.
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