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Update README and clean up tests a little
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‎README.md‎

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astar-algorithm-cpp
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===================
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## astar-algorithm
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[![Build Status](https://travis-ci.org/justinhj/astar-algorithm-cpp.svg?branch=master)](https://travis-ci.org/justinhj/astar-algorithm-cpp) [![Join the chat at https://gitter.im/astar-algorithm-cpp/community](https://badges.gitter.im/astar-algorithm-cpp/community.svg)](https://gitter.im/astar-algorithm-cpp/community?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
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Summary
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-------
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### Summary
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This code is an efficient implementation in C++ and C# of the A* algorithm, designed to be used from high performance realtime applications (video games) and with an optional fast memory allocation scheme.
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This code is an efficient implementation in C++ and C# of the A* algorithm, designed to be used from high performance realtime applications (video games) and with an optional fast memory allocation scheme.
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It accompanies this A* tutorial: http://www.heyes-jones.com/astar.html
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It accompanies this A* tutorial:
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https://www.heyes-jones.com/astar.php
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The A* algorithm was described in the paper https://ieeexplore.ieee.org/document/4082128 by Hart, Nillson and Raphael.
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Sadly Nils Nillson passed away in 2019, his work is much appreciated.
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Contributions:
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* @Rasoul for submitting the path to Bucharest. Sample from Artificial Intelligence: A Modern Approach
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* @sergiosota For fixing a number of issues related to memory management
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License
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=======
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### License
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This software is released under the MIT License, see license.txt
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Commercial Use
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==============
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### Commercial Use
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This software has been used in AAA video games and is well tested in the wild. Please let me know if you use this code in your games, studies or hobby projects.
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If you feel the need to pay money for this code, it is not required by the license, but you could contribute to Unicef, a charity which helps children worldwide, http://www.unicef.org/ that would be awesome.
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Projects using this code
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========================
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### Projects using this code
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If you wish to be added to the list of known products/educational projects using the code please contact me.
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* Lighthouses AI contest https://github.com/marcan/lighthouses_aicontest
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* Self-Driving Car Engineer Nanodegree Program https://github.com/vanAken/CarND-Path-Planning-Project
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Compilation
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===========
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### Compilation
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Enter the cpp folder and run make
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Introduction
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============
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#### Introduction
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This implementation is intended to be simple to read yet fairly
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efficient. To build it you can compile, with any recent C++ compiler,
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* stlastar.h
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* optionally fsa.h
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Command line
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#### Command line
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8puzzle with no arguments runs with one of the boards in the cpp file, you can
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select the one you want changing the conditional compiliation instructions. Or if you
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TODO Make a non-deprecated compliant version using compiler checking
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Compiled with:
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Apple LLVM version 6.0 (clang-600.0.51) (based on LLVM 3.5svn)
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Please let me know if it doesn't work for you and I will try to help. I cannot help if you are using
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an old compiler such as Turbo C++, since I update the code to meet Ansi Standard C++ as required.
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Apple clang version 12.0.0 (clang-1200.0.32.28)
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Target: x86_64-apple-darwin19.6.0
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Please let me know if it does not compile on a particular platform by opening an issue.
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Cheers!
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‎cpp/tests.cpp‎

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#include <assert.h>
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#include "stlastar.h"
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// TODO this test suite is a placeholder. Should include some tests of stlastar.h functionality
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const int MAP_WIDTH = 20;
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const int MAP_HEIGHT = 20;
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int world_map[ MAP_WIDTH * MAP_HEIGHT ] =
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{
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// 0001020304050607080910111213141516171819
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 00
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1,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,1, // 01
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1,9,9,1,1,9,9,9,1,9,1,9,1,9,1,9,9,9,1,1, // 02
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1,9,9,1,1,9,9,9,1,9,1,9,1,9,1,9,9,9,1,1, // 03
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1,9,1,9,1,9,9,9,1,9,1,9,1,1,1,1,9,9,1,1, // 04
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1,9,1,1,9,1,1,1,1,9,1,1,1,1,9,1,1,1,1,1, // 05
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1,9,9,9,9,1,1,1,1,1,1,9,9,9,9,1,1,1,1,1, // 06
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1,9,9,9,9,9,9,9,9,1,1,1,9,9,9,9,9,9,9,1, // 07
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1,9,1,1,1,1,1,1,1,1,1,9,1,1,1,1,1,1,1,1, // 08
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1,9,1,9,9,9,9,9,9,9,1,1,9,9,9,9,9,9,9,1, // 09
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1,9,1,1,1,1,9,1,1,9,1,1,1,1,1,1,1,1,1,1, // 10
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1,9,9,9,9,9,1,9,1,9,1,9,9,9,9,9,1,1,1,1, // 11
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1,9,1,9,1,9,9,9,1,9,1,9,1,9,1,9,9,9,1,1, // 12
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1,9,1,9,1,9,9,9,1,9,1,9,1,9,1,9,9,9,1,1, // 13
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1,9,1,1,1,1,9,9,1,9,1,9,1,1,1,1,9,9,1,1, // 14
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1,9,1,1,9,1,1,1,1,9,1,1,1,1,9,1,1,1,1,1, // 15
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1,9,9,9,9,1,1,1,1,1,1,9,9,9,9,1,1,1,1,1, // 16
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1,1,9,9,9,9,9,9,9,1,1,1,9,9,9,1,9,9,9,9, // 17
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1,9,1,1,1,1,1,1,1,1,1,9,1,1,1,1,1,1,1,1, // 18
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 19
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};
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// map helper functions
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int GetMap( int x, int y )
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{
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if( x < 0 ||
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x >= MAP_WIDTH ||
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y < 0 ||
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y >= MAP_HEIGHT
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)
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{
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return 9;
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}
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return world_map[(y*MAP_WIDTH)+x];
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}
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// Definitions
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class MapSearchNode
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{
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public:
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int x; // the (x,y) positions of the node
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int y;
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MapSearchNode() { x = y = 0; }
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MapSearchNode( int px, int py ) { x=px; y=py; }
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float GoalDistanceEstimate( MapSearchNode &nodeGoal );
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bool IsGoal( MapSearchNode &nodeGoal );
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bool GetSuccessors( AStarSearch<MapSearchNode> *astarsearch, MapSearchNode *parent_node );
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float GetCost( MapSearchNode &successor );
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bool IsSameState( MapSearchNode &rhs );
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void PrintNodeInfo();
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};
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bool MapSearchNode::IsSameState( MapSearchNode &rhs )
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{
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// same state in a maze search is simply when (x,y) are the same
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if( (x == rhs.x) &&
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(y == rhs.y) )
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{
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return true;
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}
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else
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{
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return false;
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}
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}
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void MapSearchNode::PrintNodeInfo()
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{
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char str[100];
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sprintf( str, "Node position : (%d,%d)\n", x,y );
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cout << str;
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}
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// Here's the heuristic function that estimates the distance from a Node
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// to the Goal.
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float MapSearchNode::GoalDistanceEstimate( MapSearchNode &nodeGoal )
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{
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return abs(x - nodeGoal.x) + abs(y - nodeGoal.y);
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}
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bool MapSearchNode::IsGoal( MapSearchNode &nodeGoal )
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{
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if( (x == nodeGoal.x) &&
115+
(y == nodeGoal.y) )
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{
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return true;
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}
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return false;
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}
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// This generates the successors to the given Node. It uses a helper function called
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// AddSuccessor to give the successors to the AStar class. The A* specific initialisation
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// is done for each node internally, so here you just set the state information that
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// is specific to the application
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bool MapSearchNode::GetSuccessors( AStarSearch<MapSearchNode> *astarsearch, MapSearchNode *parent_node )
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{
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int parent_x = -1;
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int parent_y = -1;
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if( parent_node )
134+
{
135+
parent_x = parent_node->x;
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parent_y = parent_node->y;
137+
}
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MapSearchNode NewNode;
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// push each possible move except allowing the search to go backwards
143+
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if( (GetMap( x-1, y ) < 9)
145+
&& !((parent_x == x-1) && (parent_y == y))
146+
)
147+
{
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NewNode = MapSearchNode( x-1, y );
149+
astarsearch->AddSuccessor( NewNode );
150+
}
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if( (GetMap( x, y-1 ) < 9)
153+
&& !((parent_x == x) && (parent_y == y-1))
154+
)
155+
{
156+
NewNode = MapSearchNode( x, y-1 );
157+
astarsearch->AddSuccessor( NewNode );
158+
}
159+
160+
if( (GetMap( x+1, y ) < 9)
161+
&& !((parent_x == x+1) && (parent_y == y))
162+
)
163+
{
164+
NewNode = MapSearchNode( x+1, y );
165+
astarsearch->AddSuccessor( NewNode );
166+
}
167+
168+
169+
if( (GetMap( x, y+1 ) < 9)
170+
&& !((parent_x == x) && (parent_y == y+1))
171+
)
172+
{
173+
NewNode = MapSearchNode( x, y+1 );
174+
astarsearch->AddSuccessor( NewNode );
175+
}
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177+
return true;
178+
}
179+
180+
// given this node, what does it cost to move to successor. In the case
181+
// of our map the answer is the map terrain value at this node since that is
182+
// conceptually where we're moving
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184+
float MapSearchNode::GetCost( MapSearchNode &successor )
185+
{
186+
return (float) GetMap( x, y );
187+
188+
}
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10190
int main(int argc, char *argv[]) {
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192+
AStarSearch<MapSearchNode> astarsearch;
193+
194+
unsigned int SearchCount = 0;
195+
196+
const unsigned int NumSearches = 1;
197+
198+
while(SearchCount < NumSearches)
199+
{
200+
201+
// Create a start state
202+
MapSearchNode nodeStart;
203+
nodeStart.x = 0;
204+
nodeStart.y = 0;
205+
206+
// Define the goal state
207+
MapSearchNode nodeEnd;
208+
nodeEnd.x = 3;
209+
nodeEnd.y = 3;
210+
211+
// Set Start and goal states
212+
213+
astarsearch.SetStartAndGoalStates( nodeStart, nodeEnd );
214+
215+
unsigned int SearchState;
216+
unsigned int SearchSteps = 0;
217+
218+
do
219+
{
220+
SearchState = astarsearch.SearchStep();
221+
222+
SearchSteps++;
223+
224+
#if DEBUG_LISTS
225+
226+
cout << "Steps:" << SearchSteps << "\n";
227+
228+
int len = 0;
229+
230+
cout << "Open:\n";
231+
MapSearchNode *p = astarsearch.GetOpenListStart();
232+
while( p )
233+
{
234+
len++;
235+
#if !DEBUG_LIST_LENGTHS_ONLY
236+
((MapSearchNode *)p)->PrintNodeInfo();
237+
#endif
238+
p = astarsearch.GetOpenListNext();
239+
240+
}
241+
242+
cout << "Open list has " << len << " nodes\n";
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244+
len = 0;
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cout << "Closed:\n";
247+
p = astarsearch.GetClosedListStart();
248+
while( p )
249+
{
250+
len++;
251+
#if !DEBUG_LIST_LENGTHS_ONLY
252+
p->PrintNodeInfo();
253+
#endif
254+
p = astarsearch.GetClosedListNext();
255+
}
256+
257+
cout << "Closed list has " << len << " nodes\n";
258+
#endif
259+
260+
}
261+
while( SearchState == AStarSearch<MapSearchNode>::SEARCH_STATE_SEARCHING );
262+
263+
if( SearchState == AStarSearch<MapSearchNode>::SEARCH_STATE_SUCCEEDED )
264+
{
265+
cout << "Search found goal state\n";
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MapSearchNode *node = astarsearch.GetSolutionStart();
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269+
#if DISPLAY_SOLUTION
270+
cout << "Displaying solution\n";
271+
#endif
272+
int steps = 0;
273+
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node->PrintNodeInfo();
275+
for( ;; )
276+
{
277+
node = astarsearch.GetSolutionNext();
278+
279+
if( !node )
280+
{
281+
break;
282+
}
283+
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node->PrintNodeInfo();
285+
steps ++;
286+
287+
};
288+
289+
cout << "Solution steps " << steps << endl;
290+
291+
// Once you're done with the solution you can free the nodes up
292+
astarsearch.FreeSolutionNodes();
293+
294+
295+
}
296+
else if( SearchState == AStarSearch<MapSearchNode>::SEARCH_STATE_FAILED )
297+
{
298+
cout << "Search terminated. Did not find goal state\n";
299+
300+
}
301+
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// Display the number of loops the search went through
303+
cout << "SearchSteps : " << SearchSteps << "\n";
304+
305+
SearchCount ++;
306+
307+
astarsearch.EnsureMemoryFreed();
308+
}
309+
12310
assert(true && "failed to be true");
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14312
printf("Tests succeeded\n");

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