Write a program that takes as input a positive integer N and prints out numbers 1 to N in spiral order. The number 1 is at center of the spiral and the numbers spiral outward counter-clockwise. E.g. if N = 100, the program should output:
Solution:
using System;
namespace MyApp
{
class Program
{
static void Main(string[] args)
{
if (args.Length >= 1)
{
int N;
if (int.TryParse(args[0], out N))
{
if (N > 0)
{
var d = Math.Sqrt(N);
var m = (int)Math.Ceiling((d - 1) / 2);
var p = 2 * m + 1;
var a = new int[p, p];
fill(a, m, m, N);
print(a, N);
}
}
}
}
static void print (int[,] a, int N)
{
int L = N.ToString().Length;
int p = a.GetLength(0);
var fmt = "{0," + L + "} ";
for(int row = 0; row < p; row++)
{
for(int col = 0; col < p; col++)
{
if (a[row, col] == 0)
{
Console.Write(fmt, string.Empty);
}
else
{
Console.Write(fmt, a[row, col]);
}
}
Console.WriteLine();
}
}
static void fill(int[,] a, int startRow, int startCol, int N)
{
int rowIncrement = 0;
int colIncrement = 1;
int row = startRow;
int col = startCol;
int ctr = 0;
int L = 1;
bool ff = false;
for(int i = 1; i <= N; i++, row += rowIncrement, col += colIncrement, ctr++)
{
a[row, col] = i;
if (ctr == L)
{
changeDirection(ref rowIncrement, ref colIncrement);
ctr = 0;
if (ff)
{
L++;
}
ff = !ff;
}
}
}
static void changeDirection(ref int r, ref int c)
{
if (r == 0 && c == 1)
{
r = -1;
c = 0;
}
else if (r == -1 && c == 0)
{
r = 0;
c = -1;
}
else if (r == 0 && c == -1)
{
r = 1;
c = 0;
}
else if (r == 1 && c == 0)
{
r = 0;
c = 1;
}
else
{
throw new InvalidOperationException();
}
}
}
}
siddharth's space 