Plus One

Solution

You are given a large integer represented as an integer array digits, where each digits[i] is the ith digit of the integer. The digits are ordered from most significant to least significant in left-to-right order. The large integer does not contain any leading 0's.

Increment the large integer by one and return the resulting array of digits.

 

 

Examples

 

 

Explanation

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

 

In case the given array is [1, 2, 3]

If the digits[i] is less than 9, increment digits[i] and will directly return the array. 

 

In case the given array is [2, 1, 9]

If the digits[i] is not less than 9, means that it only has to be 9 then digits is changed to zero. The for loop then iterates through the array and check for number whether it is less than 9 or not.

 

In case the given array is [9, 9, 9]

It will become [0, 0, 0] according to the above loop. To increment the array, make a new array with length + 1 and change the first value of array to 1 and return newArr, [1, 0, 0, 0].