From 1955dd8bceb1bd5beef449ff1ac04c35c2714f31 Mon Sep 17 00:00:00 2001
From: Scott Worley <scottworley@scottworley.com>
Date: Sat, 9 Jan 2016 21:59:30 -0800
Subject: [PATCH] Keep a count of live Steps

---
 sliding_tile_lib.cc | 12 ++++++++++--
 sliding_tile_lib.h  |  2 ++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/sliding_tile_lib.cc b/sliding_tile_lib.cc
index 9f6bfc9..51aeded 100644
--- a/sliding_tile_lib.cc
+++ b/sliding_tile_lib.cc
@@ -12,6 +12,7 @@
 
 #include <iostream>
 
+int Step::count = 0;
 signed char Step::adjacent[BOARD_SIZE][5] = {
   1,   4,   -1,  -1,  -1,
   0,   2,   5,   -1,  -1,
@@ -138,7 +139,13 @@ int Board::distance(const InvertedBoard& invo) const {
   return dist;
 }
 
-Step::Step(Board board, std::shared_ptr<Step> prev) : board(board), prev(prev) {}
+Step::Step(Board board, std::shared_ptr<Step> prev) : board(board), prev(prev) {
+  count++;
+}
+
+Step::~Step() {
+  count--;
+}
 
 std::vector<std::shared_ptr<Step>> Step::successors(std::shared_ptr<Step> shared_this) const {
   std::vector<std::shared_ptr<Step>> suc;
@@ -215,7 +222,8 @@ std::shared_ptr<Step> find_path(const Board& start, const Board& goal) {
         seen.emplace(s->board);
         todo.push(s);
         if (seen.size() % 10000 == 0) {
-          std::cerr << "Examined " << seen.size() << " boards.  " << todo.size()
+          std::cerr << "Examined " << seen.size() << " boards.  Tracking "
+                    << Step::count << " steps.  " << todo.size()
                     << " waiting.  Considering paths of length "
                     << todo.top()->cost(invgoal) << std::endl;
         }
diff --git a/sliding_tile_lib.h b/sliding_tile_lib.h
index de2ca1f..11d9de3 100644
--- a/sliding_tile_lib.h
+++ b/sliding_tile_lib.h
@@ -30,6 +30,7 @@ std::ostream& operator<<(std::ostream& os, const Board& board);
 
 struct Step {
   Step(Board board, std::shared_ptr<Step> prev);
+  ~Step();
 
   Board board;
   std::shared_ptr<Step> prev;
@@ -39,6 +40,7 @@ struct Step {
   int cost(const InvertedBoard& invgoal) const;
 
   static signed char adjacent[BOARD_SIZE][5];
+  static int count;
 };
 std::ostream& operator<<(std::ostream& os, const Step& step);
 
-- 
2.44.1