EasyArraysAI interview only
Plus One
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01 · Problem
A non-negative integer is stored as an array digits, where each element is a single decimal digit and the most significant digit comes first. The number has no leading zeros, except for the number 0 itself, which is represented as [0].
Add one to the number and return the digits of the result in the same format.
02 · Examples
Example 01
Input
digits = [1,2,3]
Output
[1,2,4]
The array represents 123, and 123 + 1 = 124.
Example 02
Input
digits = [4,3,2,1]
Output
[4,3,2,2]
The array represents 4321, and 4321 + 1 = 4322.
Example 03
Input
digits = [9,9]
Output
[1,0,0]
99 + 1 = 100; the carry ripples through every digit and adds a new leading 1.
03 · Constraints
- 011 <= digits.length <= 100
- 020 <= digits[i] <= 9
- 03digits has no leading zeros unless it is exactly [0]
04 · Optimal complexity
- Time
- O(n)
- Space
- O(1)
05 · Two ways to work on it
Practice it alone or rehearse it as an interview.
Practice Mode gives you an editor and test runs, nothing else. AI Interview Mode puts a voice interviewer on the other side, adds a clock, and ends with a scored summary of the round.