66. Plus One

Given a non-empty array of digits representing a non-negative integer, plus one to the integer.

The digits are stored such that the most significant digit is at the head of the list, and each element in the array contain a single digit.

You may assume the integer does not contain any leading zero, except the number 0 itself.

Example 1:

Input: [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123.

Example 2:

Input: [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321.

	class Solution {
	public int[] plusOne(int[] digits) {
	List<Integer> list = new ArrayList<Integer>();

	for (int i = digits.length - 1; i >= 0; i--) {
	if (digits[i] < 9) {
	digits[i]++;
	// no carry => found ans
	return digits;
	} else {
	digits[i] = 0;
	}
	}

	int[] ans = new int[digits.length + 1];
	// Did not return so far => carry 1 to Most significant bit
	ans[0] = 1;

	for (int i = 0; i < digits.length; i++) {
	ans[i + 1] = digits[i];
	}
	return ans;
	}
	}

	class Solution:
	def plusOne(self, digits: List[int]) -> List[int]:
	for i in range(len(digits) - 1, -1, -1):
	if digits[i] < 9:
	digits[i] += 1
	return digits

	digits[i] = 0

	return [1] + digits

view raw 66.PlusOne.py hosted with ❤ by GitHub

	class Solution {
	public int[] plusOne(int[] digits) {
	List<Integer> list = new ArrayList<Integer>();

	int sum = 0, carry = 1;

	for (int i = digits.length - 1; i >= 0; i--) {
	sum = (carry + digits[i]) % 10;
	list.add(sum);

	carry = (carry + digits[i]) / 10;
	}
	if (carry > 0) {
	list.add(carry);
	}

	Collections.reverse(list);
	int[] ans = new int[list.size()];

	for (int i = 0; i < list.size(); i++) {
	ans[i] = list.get(i);
	}
	return ans;
	}
	}

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