http://oj.leetcode.com/problems/plus-one/

Plus One.java

public class Solution {
    public int[] plusOne(int[] digits) {
        int length = digits.length;
        int plus = 1;
        for (int i = length - 1; i >= 0; i--){
            digits[i] += plus;
            if (digits[i] >= 10){
                plus = 1;
                digits[i] -= 10;
            } else {
                plus = 0;
            }
        }
        if (plus == 0){
            return digits;
        }else{
            int[] ret = new int[length + 1];
            ret[0] = 1;
            for (int i = 1; i < length + 1; i++){
                ret[i] = digits[i - 1];
            }
            return ret;
        }
    }
}