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

   1 #include "sliding_tile_lib.h"
   2
   3 #include <istream>
   4 #include <stdexcept>
   5
   6 signed char adjacent[BOARD_SIZE][5] = {
   7   1,   4,   -1,  -1,  -1,
   8   0,   2,   5,   -1,  -1,
   9   1,   3,   6,   -1,  -1,
  10   2,   7,   -1,  -1,  -1,
  11   0,   5,   8,   -1,  -1,
  12   1,   4,   6,   9,   -1,
  13   2,   5,   7,   10,  -1,
  14   3,   6,   11,  -1,  -1,
  15   4,   9,   12,  -1,  -1,
  16   5,   8,   10,  13,  -1,
  17   6,   9,   11,  14,  -1,
  18   7,   10,  15,  -1,  -1,
  19   8,   13,  -1,  -1,  -1,
  20   9,   12,  14,  -1,  -1,
  21   10,  13,  15,  -1,  -1,
  22   11,  14,  -1,  -1,  -1,
  23 };
  24
  25 bool Board::is_valid() const {
  26   bool seen[BOARD_SIZE];
  27   for (int i = 0; i < BOARD_SIZE; i++) {
  28     seen[i] = false;
  29   }
  30
  31   for (int i = 0; i < BOARD_SIZE; i++) {
  32     if (board[i] < 0 || board[i] >= BOARD_SIZE || seen[board[i]]) {
  33       return false;
  34     }
  35     seen[board[i]] = true;
  36   }
  37
  38   // Redundant because pigeon-hole-principle, but check anyway
  39   for (int i = 0; i < BOARD_SIZE; i++) {
  40     if (!seen[i]) {
  41       return false;
  42     }
  43   }
  44
  45   return true;
  46 }
  47
  48 std::istream& operator>>(std::istream& is, Board& board) {
  49   for (int i = 0; i < BOARD_SIZE; i++) {
  50     if (!is.good()) {
  51       is.setstate(std::istream::failbit);
  52       break;
  53     }
  54     if (i > 0 && is.get() != ',') {
  55       is.setstate(std::istream::failbit);
  56       break;
  57     }
  58     int numeric;
  59     is >> numeric;
  60     board.board[i] = numeric;
  61   }
  62   if (!board.is_valid()) {
  63     is.setstate(std::istream::failbit);
  64   }
  65   return is;
  66 }
  67
  68 signed char Board::hole() const {
  69   for (int i = 0; i < BOARD_SIZE; i++) {
  70     if (board[i] == 0) {
  71       return i;
  72     }
  73   }
  74   throw std::runtime_error("Board with no hole");
  75 }