LeetCode - Plus one

PlusOne

public class Solution {
    public int[] plusOne(int[] array) {
        if (array == null) return null;
        int carry = 0; 
        for(int i = array.length-1; i >= 0; i--) {
            array[i] += (i == array.length-1 ? 1+carry : carry);
            carry = array[i]/10;
            array[i] %= 10;
        }
        if(carry == 0) return array;
        else {
            int[] newArray = new int[array.length+1];
            for(int i = 0; i < array.length; i++)
                newArray[i+1] = array[i];
            newArray[0] = carry;
            return newArray;
        }
    }
}

time complexity is O(n) and space complexity is O(n) (worse case), best case is O(1)