Generate successor boards

[slidingtile] / sliding_tile_lib.cc

diff --git a/sliding_tile_lib.cc b/sliding_tile_lib.cc
index aee8380c421fe11036f4c9bc957cca971edf6eca..b43cbbaa939df7b79172ecc7a528da67ebf23d79 100644 (file)
--- a/sliding_tile_lib.cc
+++ b/sliding_tile_lib.cc
@@ -2,10 +2,12 @@
 
 #include <cstdlib>
 #include <istream>
+#include <memory>
 #include <ostream>
 #include <stdexcept>
+#include <vector>
 
-signed char adjacent[BOARD_SIZE][5] = {
+signed char Step::adjacent[BOARD_SIZE][5] = {
   1,   4,   -1,  -1,  -1,
   0,   2,   5,   -1,  -1,
   1,   3,   6,   -1,  -1,
@@ -106,3 +108,13 @@ int Board::distance(const InvertedBoard& invo) const {
   }
   return dist;
 }
+
+std::vector<Step*> Step::successors(std::shared_ptr<Step> shared_this) {
+  std::vector<Step*> suc;
+  signed char hole_pos = board.hole();
+  for (int i = 0; adjacent[hole_pos][i] > 0; i++) {
+    suc.emplace_back(new Step{board, shared_this});
+    std::swap(suc.back()->board.board[hole_pos], suc.back()->board.board[adjacent[hole_pos][i]]);
+  }
+  return suc;
+}