Given a non-negative integer represented as a non-empty array of digits, plus one to the integer.

You may assume the integer do not contain any leading zero, except the number 0 itself.

The digits are stored such that the most significant digit is at the head of the list.

public class Solution {
    public int[] plusOne(int[] digits) {
        for(int i=digits.length -1 ; i>=0;i--){
            if(digits[i] <9){
                digits[i]++;
                return digits;
            }
            digits[i] = 0;
        }
        if(digits[0] == 0){
            int[] newn = new int[digits.length+1];
            newn[0] =1;
            return newn;
        }
        else{
            return digits;
        }
        
    }
}