X-Git-Url: http://git.scottworley.com/slidingtile/blobdiff_plain/9b1ce99505059bba03b178c45721c73f3d36fb35..310a7132ffc617b93969703de7f3bf1c5ea0fa30:/sliding_tile_lib.cc

diff --git a/sliding_tile_lib.cc b/sliding_tile_lib.cc
index 6b42f28..e4f2f12 100644
--- a/sliding_tile_lib.cc
+++ b/sliding_tile_lib.cc
@@ -62,6 +62,17 @@ bool Board::operator!=(const Board& o) const {
   return !operator==(o);
 }
 
+bool Board::operator<(const Board& o) const {
+  for (int i = 0; i < BOARD_SIZE; i++) {
+    if (board[i] < o.board[i]) {
+      return true;
+    } else if (board[i] > o.board[i]) {
+      return false;
+    }
+  }
+  return false;
+}
+
 std::istream& operator>>(std::istream& is, Board& board) {
   for (int i = 0; i < BOARD_SIZE; i++) {
     if (!is.good()) {