# 66 Plus One

You are given a large integer represented as an integer array `digits`, where each `digits[i]` is the `ith` digit of the integer. The digits are ordered from most significant to least significant in left-to-right order. The large integer does not contain any leading `0`'s.

Increment the large integer by one and return the resulting array of digits.

Example 1:

``````Input: digits = [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123.
Incrementing by one gives 123 + 1 = 124.
Thus, the result should be [1,2,4].
``````

Example 2:

``````Input: digits = [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321.
Incrementing by one gives 4321 + 1 = 4322.
Thus, the result should be [4,3,2,2].
``````

Example 3:

``````Input: digits = [9]
Output: [1,0]
Explanation: The array represents the integer 9.
Incrementing by one gives 9 + 1 = 10.
Thus, the result should be [1,0].
``````

Constraints:

• `1 <= digits.length <= 100`
• `0 <= digits[i] <= 9`
• `digits` does not contain any leading `0`'s.
 `````` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 `````` ``````class Solution: def plusOne(self, digits: List[int]) -> List[int]: digits[-1] += 1 res = [] carry = 0 for i in range(len(digits)-1, -1, -1): res.append((digits[i] + carry) % 10) carry = (digits[i] + carry) // 10 if carry > 0: res.append(1) return reversed(res) ''' Early termination ''' class Solution: def plusOne(self, digits: List[int]) -> List[int]: n = len(digits) # move along the input array starting from the end for i in range(n): idx = n - 1 - i # set all the nines at the end of array to zeros if digits[idx] == 9: digits[idx] = 0 # here we have the rightmost not-nine else: # increase this rightmost not-nine by 1 digits[idx] += 1 # and the job is done return digits # we're here because all the digits are nines return [1] + digits``````