# 66. Plus One

[Link](https://leetcode.com/problems/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.
```

Solution

這題沒什麼難度，注意一下以下test case:

input: \[9]&#x20;

output: \[1, 0]\
\
若output的位數比原本的digits提供的多，要建立一個新array去return

```
 public int[] plusOne(int[] digits) {
        boolean isOverflowed = true;
        for(int i = digits.length - 1; i >= 0 ; i--){
            if(isOverflowed){
                digits[i]++;
                if(digits[i] >= 10){
                    digits[i] = digits[i]%10;
                }else{
                    return digits;
                }
            }
        }
        int[] ret = new int[digits.length + 1];
        ret[0] = 1;
        for(int i = 1; i < digits.length + 1; i ++){
            ret[i] = digits[i-1];
        }
        
        return ret;
    }
```
