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POBreadth first search not working 100%
 

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  1. POBreadth first search not working 100%
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    <p>working on doing a bfs for an adjacency matrix which is buil as an array of linked lists.</p> <p>Here is my bfs method, receives the array of linked lists and starting location:</p> <pre><code>public static int bfs(List&lt;Integer&gt;[] smallWorld, int start){ int distance = 0; int size = smallWorld.length; //for each location in smallWorld do a bfs to every other location int u; int white = 0, grey = 1, black = 2; int [] color, d, pie; Queue &lt;Integer&gt; q = new &lt;Integer&gt; LinkedList(); color = new int [size]; d = new int [size]; pie = new int [size]; for( int x = 0; x &lt; size; x++){ color[x] = white; d[x] = -1; pie[x] = -1; } color[start] = grey; d[start] = 0; pie[start] = -1; q.addAll(smallWorld[start]); //enqueue the adjacent items while(!q.isEmpty()){ u = q.remove(); for(int v = 0; v &lt; smallWorld[u].size(); v++){ //for every vertex u is adjacent to if(color[v] == white){ color[v] = grey; d[v] = d[u] + 1; pie[v] = u; q.addAll(smallWorld[v]); } } color[u] = black; } int x = 0; while(d[x] != -1){ distance = distance + d[x]; x++; } </code></pre> <p>Really smallWorld is of length 500, but for testing purposes im just doing a bfs on the first index in the array. (Ya know bfs is supposed to give back the shortest possible path between 2 indexes in the array). Mine has been running for about 14 min now and im not sure why, i mean i assume its because the !isEmpty() but that only adds stuff to the queue if its white so sooner or later that has to run out.</p> <p><strong>EDITED. FIGURED OUT ENDLESS LOOP PROBLEM BUT BFS METHOD STILL NOT 100%</strong></p> <p>any ideas why it isnt working? I mean i followed the algorithm to the T, but the algorithm generally isnt referring to an array of linked lists.</p> <p>Any ideas to solve this problem</p>
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    1. USerp
    1. USerp
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    1. CODid you try to debug the code? Or just printing sysouts atleast?
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      1. USShreyas Mahajan
    2. COyea i was doing printouts but figured out why it was running forever. but my bfs method still doesnt work, also cant figure that out. I followed the algorithm.
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      1. USerp
 

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