Self-hatred

Project Euler Problem #24

00:00:00.0716283

This one hurt my head, even after I was led onto Narayana Pandita’s algorithm. The algorithm depends on finding the largest integer that is smaller than another integer in the sequence/array; however, I’ve looked at several code solutions that just come in from the right and pick the first integer that is smaller than another. So here I am!

Time to start studying for my repeat XNA exam.

using System;

public class TwentyFour
{
	static void Main()
	{
		int[] a = {0,1,2,3,4,5,6,7,8,9};	
		int   b = 1;
		int 	c = 1000000;

		while (b < c)
		{	
			a = Permute(a);
			b++;
		}

		Print(a);
	}

	static void Print(int[] z)
	{
		Console.WriteLine();
		for (int i = 0; i < z.Length; i++)
			Console.Write(z[i]);
		Console.WriteLine("n");
	}

	static int[] Permute(int[] z)
	{
		int k = -1;
		int l =  0;

		for (int i = (z.Length - 2); i >= 0; i--)
			if (z[i] < z[i + 1])
			{
				k = i;
				break;
			}

		for (int i = z.Length - 1; i > k; i--)
			if (z[i] > z[k])
			{
				l = i;
				break;
			}

		int tmp = z[k];
		z[k] = z[l];
		z[l] = tmp;

		Array.Reverse(z, k + 1, z.Length - (k + 1));
		return z;
	}
}

Tagged with: 24, c, csharp, lexicographic, permutation, problem, project euler, projecteuler, solution, twenty four

Categorised as: programming