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POCan't create a list of elements linked by a "Parent"
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  1. POCan't create a list of elements linked by a "Parent"
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    copied!<p>I'm trying to create a method (using the *A** algorithm) that solves a puzzle and returns the steps to that solution. The solution it's easy.. but I can't return the path to that.</p> <p>I used a list of Nodes and then every time a push back a new Node I set the parent pointing to the Node which new came;</p> <pre><code>list&lt;Node&gt; opened; list&lt;Node&gt; closed; Node current; opened.push_back(start); while( opened.size() !=0 ) { current = getLowestCostPath(opened); if(IsSolution(current) == true) return opened; opened.remove(current); if( !Has(closed, current)) closed.push_back(current); for( int i = 0; i &lt; static_cast&lt;int&gt;(current.GetBoard().capacity()); i++ ) { xx = current.GetBoard()[i].X(); yy = current.GetBoard()[i].Y(); for(int j = 0; j &lt; static_cast&lt;int&gt;(current.GetBoard().capacity()); j++) { if( isMovable(current)) { //if found a new node Node newNode = Node(newBoard); Node *t = &amp;current; if(!Has(opened, newNode ) &amp;&amp; !Has(closed, newNode ) ) { newNode.SetParent(t); opened.push_back(newPath); } } } } } (..) </code></pre> <p>the class Node it's just this</p> <pre><code>class Node{ public: std::vector&lt;Point&gt; board; Path *parent; Node(); Node(std::vector&lt;Point&gt; board) virtual std::vector&lt;Point&gt; GetBoard() const; virtual Path* GetParent() const; virtual void SetParent(Node *p); </code></pre> <hr> <pre><code>Node::Node(): board(),parent(NULL) { } std::vector&lt;Point&gt; Node::GetBoard() const { return board; } void Path::SetParent(Node *p) { this-&gt;parent = p; } Path* Path::GetParent() const { return parent; } </code></pre> <p>But then I realized that I can't BUILD the path to solve the puzzle...</p> <p>I can't even see a single Parent board...</p> <pre><code>for( list&lt;Node&gt;::iterator it = goal.begin(); it != goal.end(); it++) { if( (*it).GetParent() != NULL ){ cout &lt;&lt; "writing a board" &lt;&lt; endl; mas::WriteLine( (*it).GetParent()-&gt;GetBoard() , "\n"); } } </code></pre> <p>I've searched all over the internet and I can't realize what am I doing wrong :(</p> <hr> <p><strong>I also tried this but it makes VS2005 Crash.</strong></p> <p>//goal it's the opened list that the method Solve returned....</p> <pre><code>for(std::list&lt;Node&gt;::iterator it = goal.end(); it-&gt;GetParent() != NULL; t-&gt;GetParent()) { std::cout &lt;&lt; "step" &lt;&lt; std::endl; mas::WriteLine((*it).GetBoard(), "\n"); } </code></pre> <hr> <p>I'm trying to be more clear and objective. So... see this parts</p> <pre><code>current = getLowestCostPath(opened); </code></pre> <p>The value returned by the method getLowestCostPath came from:</p> <pre><code>Node Solution::getLowestCostPath( std::list&lt;Node&gt; l) { std::list&lt;Node&gt;::reverse_iterator min = l.rbegin(); int value = 0; for(std::list&lt;Node&gt;::reverse_iterator it = l.rbegin(); it != l.rend(); it++) { if( value &lt; (*it).GetStep()) { min = it; value = (*it).GetStep(); } } return *min; } </code></pre> <p>after that... on the method Solve.. there is this part of the code</p> <pre><code>//if found a new node Node newNode = Node(newBoard); Node *t = &amp;current; newPath.SetParent(t); </code></pre> <p>I think that the ERROR it's on this part, <em>newPath</em> it's pointing to <em>t</em> when it should be pointing to node on the list <em>opened</em></p> <p>Is it true? If it is.. how can I fix this?</p>
 

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