LeetCode/58. LengthOfLastWord & LeetCode/66. PlusOne

Link

• https://leetcode.com/problems/length-of-last-word
• https://leetcode.com/problems/plus-one

Summary

1. Length Of Last Word is not even a algorithm question.
   
2. PlusOne was really easy but I was making a simple mistake which should be handled.
   

Solutions

My Solution

I’ll skip explaining #58.

public int Solution(string s)
{
    var res = 0;
    for (int i = s.Length - 1; i >= 0; i--)
    {
        if (Char.IsWhiteSpace(s[i]))
        {
            if (res != 0) return res;
            res = 0;
            continue;
        }
        res++;
    }
    return res;
}

1. PlusOne was interesting because I was missing two thing.
   

2. I was not using pen & paper and write those down.

3. I was missing the case like [9, 9] which will make a new array like as [1, 0, 0].

I should think about these cases.

public int[] Solution(int[] digits)
{
    var reminder = 1;
    for (int i = digits.Length - 1; i >= 0; i--)
    {
        digits[i] += reminder;

        if (digits[i] >= 10)
        {
            digits[i] = 0;
            reminder = 1;
            continue;
        }
        reminder = 0;

        break;
    }

    if (reminder != 0) {
        var arr = new int[digits.Length + 1];
        arr[0] = reminder;
        Array.Copy(digits, 0, arr, 1, digits.Length);
        return arr;
    }
    return digits;
}