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[slidingtile] / 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() {
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() {
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 }