leetcode 66. Plus One

題目

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.

解

public class Solution {
  public int[] plusOne(int[] digits) {

            int j=digits.length-1;
            digits[j]+=1;
            while(j>0){
                if(digits[j]>9){
                    digits[j]=digits[j]-10;
                    digits[j-1]+=1;
                }

                j--;
            }


            if(digits[0]<10){
                return digits;
            }else
            {
                 int carry=0;
                 if(digits[0]>9){
                        digits[0]=digits[0]-10;
                        carry=1;
                 }
                 int[] ret=new int[digits.length+1];
                 ret[0]=carry;
                 for(int i=1;i<ret.length;i++){
                     ret[i]=digits[i-1];
                 }
                 return ret;

            }

        }
}