X-Git-Url: http://git.scottworley.com/slidingtile/blobdiff_plain/1955dd8bceb1bd5beef449ff1ac04c35c2714f31..ab51c07a99c1927c95a123e6912925adba83714f:/sliding_tile_lib.cc?ds=sidebyside

diff --git a/sliding_tile_lib.cc b/sliding_tile_lib.cc
index 51aeded..9ac0217 100644
--- a/sliding_tile_lib.cc
+++ b/sliding_tile_lib.cc
@@ -133,8 +133,10 @@ int Board::distance(const Board& o) const {
 int Board::distance(const InvertedBoard& invo) const {
   int dist = 0;
   for (int i = 0; i < BOARD_SIZE; i++) {
-    dist += std::abs(i % BOARD_DIM - invo.pos[board[i]] % BOARD_DIM) +
-            std::abs(i / BOARD_DIM - invo.pos[board[i]] / BOARD_DIM);
+    if (board[i] != 0) {
+      dist += std::abs(i % BOARD_DIM - invo.pos[board[i]] % BOARD_DIM) +
+              std::abs(i / BOARD_DIM - invo.pos[board[i]] / BOARD_DIM);
+    }
   }
   return dist;
 }