leetcode — plus-one

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
* Source : https://oj.leetcode.com/problems/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.
*
*/
public class PlusOne {

/**
* 加法运算，注意进位
*
* @param digit
* @return
*/
public Integer[] plusOne (int[] digit) {
int carry = 1;
List<Integer> result = new ArrayList<Integer>();
for (int i = digit.length - 1; i > -1; i--) {
carry += digit[i];
result.add(0, carry % 10);
carry = carry / 10;
}
if (carry > 0) {
result.add(0, carry);
}
return result.toArray(new Integer[result.size()]);
}

public static void main(String[] args) {
PlusOne plusOne = new PlusOne();
int[] arr = new int[]{1,2,3};
int[] arr1 = new int[]{1,9,9};
int[] arr2 = new int[]{9,9,9};
int[] arr3 = new int[]{1};
int[] arr4 = new int[]{9};
int[] arr5 = new int[]{};

System.out.println(Arrays.toString(plusOne.plusOne(arr)));
System.out.println(Arrays.toString(plusOne.plusOne(arr1)));
System.out.println(Arrays.toString(plusOne.plusOne(arr2)));
System.out.println(Arrays.toString(plusOne.plusOne(arr3)));
System.out.println(Arrays.toString(plusOne.plusOne(arr4)));
System.out.println(Arrays.toString(plusOne.plusOne(arr5)));
}
}