LeetCode/7. ReverseInteger & LeetCode/9. PalindromeNumber

Preface

I’m trying to take a Easy difficulty ones to warm up my coding practice.

https://leetcode.com/problems/reverse-integer/ https://leetcode.com/problems/palindrome-number/

Summary

Solving these two problem wasn’t hard. Both are asking the same thing. Can you pop number from integer rather than using string
However re-learning that pop = x % 10 & x /= 10

Solution

7.ReverseInteger

public class ReverseInteger
{
    public int Solution(int x)
    {
        var str = x.ToString();
        var leng = x < 0 ? str.Length - 1 : str.Length;
        var numDiv = (int)Math.Pow(10, leng - 1);
        var mul = 1;
        int res = 0;

        try
        {
            for (int i = 0; i < leng; i++)
            {
                res = checked(res + (x / numDiv) * mul);
                x = x % numDiv;
                numDiv /= 10;
            }
        }
        catch
        {
            return 0;
        }

        return res;
    }

    public int BestSolution(int x)
    {
        int rev = 0;

        while (x != 0)
        {
            int pop = x % 10;
            x /= 10;
            if (rev > Int32.MaxValue / 10 || (rev == Int32.MaxValue / 10 && pop > 7)) return 0;
            if (rev < Int32.MinValue / 10 || (rev == Int32.MinValue / 10 && pop < -8)) return 0;
            rev = rev * 10 + pop;
        }

        return rev;
    }
}

9.PalindromeNumber

    public class PalindromeNumber
    {
        public bool IsPalindrome(int x)
        {
            if (x < 0 || (x % 10 == 0 && x != 0))
            {
                return false;
            }

            int revertedNumber = 0;
            while (x > revertedNumber)
            {
                revertedNumber = revertedNumber * 10 + x % 10;
                x /= 10;
            }

            return x == revertedNumber || x == revertedNumber / 10;
        }

        public bool IsPalindromeByConvertingString(int x)
        {
            if (x < 0) return false;

            var str = x.ToString();

            for (int i = 0; i < str.Length / 2; i++)
            {
                if (str[i] != str[str.Length - 1 - i]) return false;
            }

            return true;
        }
    }
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