/*
Syed Mehroz Alam
CIS-61
FE(CIS) Sec-A
5 June 2003
*/

#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<time.h>
#include<ctype.h>
#include<string.h>
#include<stdlib.h>
#include<dos.h>

#define MAX 10
#define sqr(n) n*n


void shuffle(void);	//shuffles the board
int found(int board[][MAX], int no);	//helper funtion for shuffling
void dispboard(void);	//displays the current contents of board
int getkey(void);	//used to track arrow keys
void swap(int x2,int y2);	//swaps x,y with x2,y2

int board[MAX][MAX];
int x,y;
int win, turns;
int ORDER;


void main(void)
{
	clrscr();
	textcolor(15);
	gotoxy(38,4); cprintf("Puzzle");
	gotoxy(38,5); cprintf("ออออออ");
	gotoxy(31,7); cprintf("by Syed Mehroz Alam");
	gotoxy(20,9);  cprintf("CIS-61, First Year, Sec-A, Batch 2002-03");
	gotoxy(20,10); cprintf("  Computer & Information Systems Dept,");
	gotoxy(20,11); cprintf("   NED University, Karachi, Pakistan.");
	gotoxy(20,13); cprintf("     Email: smehrozalam@yahoo.com");
	gotoxy(20,16); cprintf("     Press any key to begin......");
	getch();
	textcolor(7);
	printf("\n\n\t\tEnter Order (Maximum 10) : ");
	scanf("%d", &ORDER);
	if (ORDER<2 || ORDER >10)
		return;		//ends the program

	shuffle();
	dispboard();

	do
	{
		int move=0;
		while ( !(move==72 || move==80 ||move==75 || move==77 || move==1 || move==31) )
		{
			move=getkey();
		}
		if (move==1)	//escape key
			return;
		//else if arrow keys, the do respective job
		else if (move==31)
			shuffle();
		else if (move==80)
			swap(x,y-1);
		else if (move==72)
			swap(x,y+1);
		else if (move==77)
			swap(x-1,y);
		else if (move==75)
			swap(x+1,y);
		dispboard();

	}
	 while(win!=1);

	printf("\n\nCongratulations, You won in %d turns", turns);
	getch();
}


void shuffle(void)
{
	randomize();
	for (int i=0;i<ORDER;i++)
		for (int j=0;j<ORDER;j++)
			board[i][j]=0;		//empties the board

	int temp, M=sqr(ORDER)-1;
	for (i=0;i<ORDER;i++)
		for (j=0;j<ORDER;j++)
		{
			if (i==ORDER-1 && j==ORDER-1)
			{
				board[i][j]=M+1;	//sets the last integer(space/gap)
				turns=0;
				x=y=ORDER-1;
				return;
			}
			do
			{
				temp=rand()%M +1;
			}
			  while ( found(board, temp) );		//the loop generates unique nos between the specific limit
			board[i][j]=temp;
		}
}


int found(int board[][MAX], int no)
{
	for (int i=0;i<ORDER;i++)
		for (int j=0;j<ORDER;j++)
			if( board[i][j]  == no)
				return 1;
	return 0;
}


void dispboard(void)
{
	clrscr();
	int i,j,chk=0;
	win=1;
	printf("Press \"Esc\" at any time to quit\n\n");
	printf("Press Arrow Keys to move\n");
	printf("Press \"S\" to shuffle\n\n\n");
	for (i=0;i<ORDER;i++)
	{
		for (j=0;j<ORDER;j++)
		{
			if (!(++chk==board[i][j] && win==1))
				win=0;
			if (board[i][j]==sqr(ORDER))
				printf("     ");
			else
				printf(" %2d  ", board[i][j]);
		}
		printf("\n\n");
	}
	printf("Turns=%d", turns);
}


int getkey(void)
{
	union REGS i,o;
	while (!kbhit())
		;
	i.h.ah=0;
	int86(22, &i, &o);
	return (o.h.ah);


}


void swap(int x2, int y2)
{
	if (x2>=0 && x2<=ORDER-1 && y2>=0 && y2<=ORDER-1)
	{
		board[y][x]=board[y2][x2];
		board[y2][x2]=sqr(ORDER);
		x=x2; y=y2;
		turns++;
	}
}