#include <stdio.h>
#include <stdlib.h>

// Initial Chess Board is empty indicated by 0s at all
// locations
char chess_board[8][8] = { {0, 0, 0, 0, 0, 0, 0, 0},
                           {0, 0, 0, 0, 0, 0, 0, 0},
                           {0, 0, 0, 0, 0, 0, 0, 0},
                           {0, 0, 0, 0, 0, 0, 0, 0},
                           {0, 0, 0, 0, 0, 0, 0, 0},
                           {0, 0, 0, 0, 0, 0, 0, 0},
                           {0, 0, 0, 0, 0, 0, 0, 0},
                           {0, 0, 0, 0, 0, 0, 0, 0} };


// Place a Queen at location X,Y on Chess Board
// Arguments are X,Y coordinates
//    Returns 1 if successful
int place_a_queen (int x, int y) {

   // Limit Verification
   if ((x > 7) || (x < 0)) {
     printf ("Error!! X coordinates out of range.. \n");
     return 0;
   }
   if ((y > 7) || (y < 0)) {
     printf ("Error!! Y coordinates out of range.. \n");
     return 0;
   }

   // Queen can be placed where there is no queen and
   // Location is not influenced by any other queen
   if (chess_board[x][y] != 0) return 0;

   // Queen Positions are indicated by 99 & affected positions are
   // indicated by 1
   chess_board[x][y] = 99;

   // Vertical Row Filling
   for (int i=0; i < 8; i++) {
     if (i != y) chess_board[x][i] += 1;
   }
    
   // Horizontal Row Filling
   for (int i=0; i < 8; i++) {
     if (i != x) chess_board[i][y] += 1;
   }

   // Diagonal  Filling
   for (int i=x+1, j=y+1; (i<8)&&(j<8); i++, j++)
     chess_board[i][j] += 1;
    
   for (int i=x-1, j=y-1; (i>=0)&&(j>=0); i--, j--)
     chess_board[i][j] += 1;
    
   for (int i=x+1, j=y-1; (i<8)&&(j>=0); i++, j--)
     chess_board[i][j] += 1;

   for (int i=x-1, j=y+1; (i>=0)&&(j<8); j++, i--)
     chess_board[i][j] += 1;

   return 1;
}

// Arguments are X,Y coordinates
//    Returns 1 if successful
int pick_a_queen (int x, int y) {

   if ((x > 7) || (x < 0)) {
     printf ("Error!! X coordinates out of range.. \n");
     return 0;
   }

   if ((y > 7) || (y < 0)) {
     printf ("Error!! Y coordinates out of range.. \n");
     return 0;
   }

   if (chess_board[x][y] != 99) return 0;

   // Queen Positions are indicated by 2 & affected positions are
   // indicated by 1
   chess_board[x][y] = 0;

   // Vertical Row Filling
   for (int i=0; i < 8; i++) {
     if (i != y) chess_board[x][i] -= 1;
   }
    
   // Horizontal Row Filling
   for (int i=0; i < 8; i++) {
     if (i != x) chess_board[i][y] -= 1;
   }

   // Diagonal  Filling
   for (int i=x+1, j=y+1; (i<8)&&(j<8); i++, j++)
     chess_board[i][j] -= 1;
    
   for (int i=x-1, j=y-1; (i>=0)&&(j>=0); i--, j--)
     chess_board[i][j] -= 1;
    
   for (int i=x+1, j=y-1; (i<8)&&(j>=0); i++, j--)
     chess_board[i][j] -= 1;

   for (int i=x-1, j=y+1; (i>=0)&&(j<8); j++, i--)
     chess_board[i][j] -= 1;

   return 1;
}