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

   1 #include "sliding_tile_lib.h"
   2
   3 #include <istream>
   4 #include <ostream>
   5 #include <stdexcept>
   6
   7 signed char adjacent[BOARD_SIZE][5] = {
   8   1,   4,   -1,  -1,  -1,
   9   0,   2,   5,   -1,  -1,
  10   1,   3,   6,   -1,  -1,
  11   2,   7,   -1,  -1,  -1,
  12   0,   5,   8,   -1,  -1,
  13   1,   4,   6,   9,   -1,
  14   2,   5,   7,   10,  -1,
  15   3,   6,   11,  -1,  -1,
  16   4,   9,   12,  -1,  -1,
  17   5,   8,   10,  13,  -1,
  18   6,   9,   11,  14,  -1,
  19   7,   10,  15,  -1,  -1,
  20   8,   13,  -1,  -1,  -1,
  21   9,   12,  14,  -1,  -1,
  22   10,  13,  15,  -1,  -1,
  23   11,  14,  -1,  -1,  -1,
  24 };
  25
  26 bool Board::is_valid() const {
  27   bool seen[BOARD_SIZE];
  28   for (int i = 0; i < BOARD_SIZE; i++) {
  29     seen[i] = false;
  30   }
  31
  32   for (int i = 0; i < BOARD_SIZE; i++) {
  33     if (board[i] < 0 || board[i] >= BOARD_SIZE || seen[board[i]]) {
  34       return false;
  35     }
  36     seen[board[i]] = true;
  37   }
  38
  39   // Redundant because pigeon-hole-principle, but check anyway
  40   for (int i = 0; i < BOARD_SIZE; i++) {
  41     if (!seen[i]) {
  42       return false;
  43     }
  44   }
  45
  46   return true;
  47 }
  48
  49 std::istream& operator>>(std::istream& is, Board& board) {
  50   for (int i = 0; i < BOARD_SIZE; i++) {
  51     if (!is.good()) {
  52       is.setstate(std::istream::failbit);
  53       break;
  54     }
  55     if (i > 0 && is.get() != ',') {
  56       is.setstate(std::istream::failbit);
  57       break;
  58     }
  59     int numeric;
  60     is >> numeric;
  61     board.board[i] = numeric;
  62   }
  63   if (!board.is_valid()) {
  64     is.setstate(std::istream::failbit);
  65   }
  66   return is;
  67 }
  68
  69 std::ostream& operator<<(std::ostream& os, const Board& board) {
  70   for (int i = 0; i < BOARD_SIZE; i++) {
  71     if (i > 0) {
  72       os << " ";
  73     }
  74     os << int(board.board[i]);
  75   }
  76   return os;
  77 }
  78
  79 signed char Board::hole() const {
  80   for (int i = 0; i < BOARD_SIZE; i++) {
  81     if (board[i] == 0) {
  82       return i;
  83     }
  84   }
  85   throw std::runtime_error("Board with no hole");
  86 }