git.scottworley.com Git - slidingtile/blob - sliding_tile_lib.cc

   1 #include "sliding_tile_lib.h"
   2
   3 #include <istream>
   4
   5 signed char adjacent[BOARD_SIZE][5] = {
   6   1,   4,   -1,  -1,  -1,
   7   0,   2,   5,   -1,  -1,
   8   1,   3,   6,   -1,  -1,
   9   2,   7,   -1,  -1,  -1,
  10   0,   5,   8,   -1,  -1,
  11   1,   4,   6,   9,   -1,
  12   2,   5,   7,   10,  -1,
  13   3,   6,   11,  -1,  -1,
  14   4,   9,   12,  -1,  -1,
  15   5,   8,   10,  13,  -1,
  16   6,   9,   11,  14,  -1,
  17   7,   10,  15,  -1,  -1,
  18   8,   13,  -1,  -1,  -1,
  19   9,   12,  14,  -1,  -1,
  20   10,  13,  15,  -1,  -1,
  21   11,  14,  -1,  -1,  -1,
  22 };
  23
  24 bool Board::is_valid() {
  25   bool seen[BOARD_SIZE];
  26   for (int i = 0; i < BOARD_SIZE; i++) {
  27     seen[i] = false;
  28   }
  29
  30   for (int i = 0; i < BOARD_SIZE; i++) {
  31     if (board[i] < 0 || board[i] >= BOARD_SIZE || seen[board[i]]) {
  32       return false;
  33     }
  34     seen[board[i]] = true;
  35   }
  36
  37   // Redundant because pigeon-hole-principle, but check anyway
  38   for (int i = 0; i < BOARD_SIZE; i++) {
  39     if (!seen[i]) {
  40       return false;
  41     }
  42   }
  43
  44   return true;
  45 }
  46
  47 std::istream& operator>>(std::istream& is, Board& board) {
  48   for (int i = 0; i < BOARD_SIZE; i++) {
  49     if (!is.good()) {
  50       is.setstate(std::istream::failbit);
  51       break;
  52     }
  53     if (i > 0 && is.get() != ',') {
  54       is.setstate(std::istream::failbit);
  55       break;
  56     }
  57     int numeric;
  58     is >> numeric;
  59     board.board[i] = numeric;
  60   }
  61   if (!board.is_valid()) {
  62     is.setstate(std::istream::failbit);
  63   }
  64   return is;
  65 }