題目

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

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

The digits are stored such that the most significant digit is at the head of the list.

答案

class Solution {
    public int[] plusOne(int[] digits) {
        int sum, carry = 1;
        int[] ans = new int[digits.length + 1];
        for(int i = digits.length - 1; i >= 0; i--) {
            sum = digits[i] + carry;
            ans[i + 1] = sum % 10;
            digits[i] = sum % 10;
            carry = (sum >= 10) ? 1:0;
            if(carry == 1 && i == 0)
                ans[0] = 1;
        }
        return (carry == 1)?ans:digits;
    }
}

class Solution {
    public int[] plusOne(int[] digits) {
        
        for(int i = digits.length - 1; i >= 0; i--) {
            if(digits[i] == 9) {
                digits[i] = 0;
                continue;
            }
            digits[i]++;
            return digits;
        }
        int[] ans = new int[digits.length + 1];
        ans[0] = 1;
        return ans;
    }
}