Tweak the default max_frontier

[slidingtile] / sliding_tile_lib.cc

diff --git a/sliding_tile_lib.cc b/sliding_tile_lib.cc
index 551bc1f018735e373fd03f0211ab7856a2625120..83d6297b42a57505164833b809a411d2050c13b7 100644 (file)
--- a/sliding_tile_lib.cc
+++ b/sliding_tile_lib.cc
@@ -1,6 +1,7 @@
 #include "sliding_tile_lib.h"
 
 #include <cstdlib>
+#include <fstream>
 #include <istream>
 #include <map>
 #include <memory>
@@ -9,6 +10,7 @@
 #include <set>
 #include <sstream>
 #include <stdexcept>
+#include <string>
 #include <vector>
 
 #include <iostream>
@@ -189,7 +191,7 @@ std::ostream& operator<<(std::ostream& os, const Step& step) {
   return os;
 }
 
-std::shared_ptr<Step> find_path(const std::string& start, const std::string& goal) {
+std::shared_ptr<Step> find_path(const std::string& start, const std::string& goal, unsigned max_frontier) {
   std::istringstream iss_start{start}, iss_goal{goal};
   Board board_start, board_goal;
   iss_start >> board_start;
@@ -200,10 +202,19 @@ std::shared_ptr<Step> find_path(const std::string& start, const std::string& goa
   if (iss_goal.fail() || !iss_goal.eof()) {
     throw std::runtime_error("Could not parse the goal board: " + goal);
   }
-  return find_path(board_start, board_goal);
+  return find_path(board_start, board_goal, max_frontier);
 }
 
-std::shared_ptr<Step> find_path(const Board& start, const Board& goal) {
+static void show_memory_stats() {
+  std::ifstream statm{"/proc/self/statm"};
+  if (statm.is_open()) {
+    std::string statm_data;
+    std::getline(statm, statm_data);
+    std::cerr << "Memory stats: " << statm_data << std::endl;
+  }
+}
+
+std::shared_ptr<Step> find_path(const Board& start, const Board& goal, unsigned max_frontier) {
   InvertedBoard invgoal = goal.invert();
   std::multimap<int, std::shared_ptr<Step>> todo;
   std::set<Board> seen;
@@ -215,6 +226,7 @@ std::shared_ptr<Step> find_path(const Board& start, const Board& goal) {
     auto cur = todo.begin()->second;
     todo.erase(todo.begin());
     if (cur->board == goal) {
+      show_memory_stats();
       return cur;
     }
     std::vector<std::shared_ptr<Step>> successors = cur->successors(cur);
@@ -230,6 +242,9 @@ std::shared_ptr<Step> find_path(const Board& start, const Board& goal) {
         }
       }
     }
+    while (todo.size() > max_frontier) {
+      todo.erase(--todo.end());
+    }
   }
   throw std::runtime_error("No path from start to goal");
 }