Challenge cum problem in C/C++

heres a hint - spiral

I know it is spiral, but how to implement it in program?

Hi Rajdeep,

Nice question dude!!!! 😁

But I am wondering......😕 if this is your home work or what......?

Any ways I know the solution buddy.......;-) it is also called as The Spiral Matrix

So this is how you implement in C++ (as well as in C 😛)

[B]/* Written by: Arvind(slashfear)
   Language: C++     */


#include <iostream>

using namespace std;

void SpiralIni(int **A, int N)
{
  int i = 0, j = 0;
  int x0 = 0, x1 = N, y0 = 0, y1 = N;
  int m = 0;
  bool up = true;

  while(1)
  {
    if(up)
    {
      for (j; j < y1; ++ j) A[i][j] = ++ m;

      -- j; ++ i; -- y1;

      for (i; i < x1; ++ i) A[i][j] = ++ m;

      -- i; -- j; -- x1;

      up = false;
    } else
    {
      for (j; j >= y0; -- j) A[i][j] = ++ m;

      ++ j; -- i; ++ y0;

      for (i; i >= x0+1; -- i) A[i][j] = ++ m;

      ++ i; ++ j; ++ x0;

      up = true;
    }

    if (m+1 > N*N) break;
  }
}

int main()
{
  int N;
  cout<<"Enter the value of N : ";
  cin>> N;
  int **a = new int* [N];
  for (int i = 0; i < N; ++ i) a[i] = new int [N];

  SpiralIni(a,N);

  for( int i = 0; i < N; ++ i)
  {
    for(int j=0; j < N; ++ j) cout<<"\t"<< a[i][j];

    cout<<"\n";
  }

  for (int i = 0; i < N; ++i) delete []a[i];
  delete []a;
return 0;
}[/B]

Output:

[B]Enter the value of N: 5

1   2   3   4   5
16  17  18  19  6
15  24  25  20  7
14  23  22  21  8
13  12  11  10  9[/B]

Mission accomplished ;-)

-Arvind(slashfear)

You are really rocking slashfear. This problem was asked in coding challenge last year in our college, but I didnt go through it. Than I suddnely remember it & I posted it here. And now I found the solution thanks to you. I want to learn lots of stuff from you. You are great!!!!

Hi Rajdeep,


No probs buddy....... knowledge is to share no need thanks and all dude😁






-Arvind(slashfear);-)

That's cool, the program work perfectly as required. Slashfear, you rock buddy.

Here is my piece of code for same problem.

#include "stdio.h"


void create_spiral(int **spiral, int spiral_size, int spiral_level) {
  int i = 0;

  //Calculating first value at level spiral_level
  int current_size = spiral_size - 2*spiral_level;
  int value = spiral_size*spiral_size - current_size*current_size + 1;

  //Populate data from left to right for spiral at level spiral_level
  for(i = 0; i < (spiral_size - 2*spiral_level); i++) {
    spiral[spiral_level][spiral_level+i] = value;
    value++;
  }

  //Populate data from top to bottom for spiral at level spiral_level
  for(i = 1; i < (spiral_size - 2*spiral_level); i++) {
    spiral[spiral_level + i][spiral_size - spiral_level - 1] = value;
    value++;
  }

  //Populate data from right to left for spiral at level spiral_level
  for(i = (spiral_size - 2*spiral_level -2); i >= 0; i--) {
    spiral[spiral_size - spiral_level -1][spiral_level + i] = value;
    value++;
  }

  //Populate data from bottom to top for spiral at level spiral_level
  for(i = (spiral_size - 2*spiral_level -2); i > 0; i--) {
    spiral[spiral_level + i][spiral_level] = value;
    value++;
  }
}


void print_spiral(int **spiral, int spiral_size) {
  int i = 0, j = 0;

  for(i = 0; i < spiral_size; i++) {
    for(j = 0; j < spiral_size; j++) {
      printf("%d ", spiral[i][j]);
    }
    printf("\n");
  }
}


int main() {
  int spiral_size = 0;
  int **spiral = NULL;
  int max_spiral_level = 0;
  int i = 0;

  //Take size of spiral as input
  scanf("%d", &spiral_size);

  //validate size of spiral
  if(spiral_size < 1) {
    printf("Invalid size for spiral\n");
    return 0;
  }

  //Allocate memory for spiral
  spiral = (int**)malloc(sizeof(int*) * spiral_size);
  for(i = 0; i < spiral_size; i++) {
    spiral[i] = (int*)malloc(sizeof(int) * spiral_size);
  }

  //Determine number of level of spiral
  max_spiral_level = (spiral_size + 1)/2;

  //For each level of spiral populate data
  for(i = 0; i < max_spiral_level; i++) {
    create_spiral(spiral, spiral_size, i);
  }

  //Print the spiral
  print_spiral(spiral, spiral_size);

  //Free memory allocated for spiral
  for(i = 0; i < spiral_size; i++) {
    free(spiral[i]);
  }
  free(spiral);

  return 0;
}

Compile the file with above code and run as:
a.exe < input.txt > output.txt [on windows]
a.out < input.txt > output.txt [on linux]

Here,
a.exe or a.out are the executables generated after compilation

input.txt is the file containing order of the spiral matrix need to be given as input, e.g., if the matrix is of order 5, then input.txt will be
5

output.txt is the output file containing result, for given example output.txt will contain
1 2 3 4 5
16 17 18 19 6
15 24 25 20 7
14 23 22 21 8
13 12 11 10 9

-Pradeep