#include "sudoku.h"

//-------------------------------------------------------------------------------------------------
// Start here to work on your MP7
//-------------------------------------------------------------------------------------------------

// You are free to declare any private functions if needed.

// Function: is_val_in_row
// Return true if "val" already existed in ith row of array sudoku.
int is_val_in_row(const int val, const int i, const int sudoku[9][9]) {

  assert(i>=0 && i<9);

  // BEG TODO
  assert(i>=0 && i<9);

  // BEG TODO
  int a=0;
  int count=0;
  for(a=0; a<9;a++){
   if(sudoku[i][a]==val)
     count++;


  }
  if (count>0)
  return 1;

  return 0;
  // END TODO
}

// Function: is_val_in_col
// Return true if "val" already existed in jth column of array sudoku.
int is_val_in_col(const int val, const int j, const int sudoku[9][9]) {

  assert(j>=0 && j<9);

  // BEG TODO
  int a=0;
  int count=0;
  for(a=0; a<9;a++){
   if(sudoku[a][j]==val)
     count++;


  }
  if (count>0)
  return 1;

  return 0;
  // END TODO
}

// Function: is_val_in_3x3_zone
// Return true if val already existed in the 3x3 zone corresponding to (i, j)
int is_val_in_3x3_zone(const int val, const int i, const int j, const int sudoku[9][9]) {

  assert(i>=0 && i<9);
  // BEG TODO
  int rw=i-i%3;
  int cl=j-j%3;
  int count=0;
  int row=rw*3;
  int col=cl*3;

  int a;
  int b;
  for(a=0;a<3;a++){
    for(b=0;b<3;b++){
      if(val==sudoku[a+rw][b+cl])
      count++;
    }
  }
  if (count>0)
  return 1;

  return 0;
  // END TODO
}

// Function: is_val_valid
// Return true if the val is can be filled in the given entry.
int is_val_valid(const int val, const int i, const int j, const int sudoku[9][9]) {

  assert(i>=0 && i<9 && j>=0 && j<9);
    // BEG TODO
  if(is_val_in_row(val, i, sudoku)==0&&is_val_in_col(val, j, sudoku)==0&&is_val_in_3x3_zone(val, i, j,sudoku)==0){
    return 1;
  }

else
  return 0;
  // END TODO
}

// Procedure: solve_sudoku
// Solve the given sudoku instance.
int solve_sudoku(int sudoku[9][9]) {

  // BEG TODO.
/*  int i, j;

if (all cells are assigned by number) {
  return true;
}
else {
  find a non-filled cell (i, j)
}

for (int num = 1; num <= 9; num++) {
  if (cell (i, j) can be filled with num) {
    sudoku[i][j] <- num;
    if (solve_sudoku(sudoku)) {
      return true;
    }
    sudoku[i][j] <- non-filled;
  }
}
return false;

  return 0;
  // END TODO.
*/
}

// Procedure: print_sudoku
void print_sudoku(int sudoku[9][9])
{
  int i, j;
  for(i=0; i<9; i++) {
    for(j=0; j<9; j++) {
      printf("%2d", sudoku[i][j]);
    }
    printf("\n");
  }
}

// Procedure: parse_sudoku
void parse_sudoku(const char fpath[], int sudoku[9][9]) {
  FILE *reader = fopen(fpath, "r");
  assert(reader != NULL);
  int i, j;
  for(i=0; i<9; i++) {
    for(j=0; j<9; j++) {
      fscanf(reader, "%d", &sudoku[i][j]);
    }
  }
  fclose(reader);
}