leetCode 66.Plus One (+1问题) 解题思路和方法

Plus One 

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

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

思路：给定一个数组，表示一个数。然后返回+1的值。主要就是进位的问题。代码例如以下：

public class Solution {
    public int[] plusOne(int[] digits) {
        int k = 1;//进位
        for(int i = digits.length - 1; i >=0 ; i--){
            digits[i] += k;//加上进位的值
            k = digits[i]/10;//进位值
            digits[i] %= 10;//留下的值
        }
        //还有进位
        if(k > 0){
            int[] a = new int[digits.length+1];
            a[0] = k;
            for(int i = 0; i < digits.length; i++){
                a[i+1] = digits[i];
            }
            return a;
        }
        return digits;
    }
}