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| 1 | +//Depth First Search Exploration Algorithm to test connectedness of the Graph (see Graph Algorithms/DFS/exploration), without the tracer & logger commands |
| 2 | +function DFSExplore (graph, source) { |
| 3 | + var stack = [ [source, null] ], visited = {}; |
| 4 | + var node, prev, i, temp; |
| 5 | + |
| 6 | + while (stack.length > 0) { |
| 7 | + temp = stack.pop (); |
| 8 | + node = temp [0]; |
| 9 | + prev = temp [1]; |
| 10 | + |
| 11 | + if (!visited [node]) { |
| 12 | + visited [node] = true; |
| 13 | + //logger._print (node); |
| 14 | + |
| 15 | + /* |
| 16 | + if (prev !== undefined && graph [node] [prev]) { tracer._visit (node, prev)._wait (); console.log ('tracer ' + prev + ', ' + node); } |
| 17 | + else { tracer._visit (node)._wait (); console.log ('tracer ' + node); } |
| 18 | + */ |
| 19 | + |
| 20 | + for (i = 0; i < graph.length; i++) { |
| 21 | + if (graph [node] [i]) { |
| 22 | + stack.push ([i, node]); |
| 23 | + } |
| 24 | + } |
| 25 | + } |
| 26 | + } |
| 27 | + |
| 28 | + return visited; |
| 29 | +} |
| 30 | + |
| 31 | +function findBridges (graph) { |
| 32 | + var tempGraph, bridges = [], visited; |
| 33 | + |
| 34 | + for (var i = 0; i < graph.length; i++) { |
| 35 | + for (var j = 0; j < graph.length; j++) { |
| 36 | + if (graph [i] [j]) { //check if an edge exists |
| 37 | + logger._print ('Deleting edge ' + i + '->' + j + ' and calling DFSExplore ()'); |
| 38 | + tracer._visit (j, i)._wait (); |
| 39 | + tracer._leave (j, i)._wait (); |
| 40 | + |
| 41 | + tempGraph = JSON.parse (JSON.stringify (graph)); |
| 42 | + tempGraph [i] [j] = 0; |
| 43 | + tempGraph [j] [i] = 0; |
| 44 | + visited = DFSExplore (tempGraph, 0); |
| 45 | + |
| 46 | + if (Object.keys (visited).length === graph.length) { |
| 47 | + logger._print ('Graph is CONNECTED. Edge is NOT a bridge'); |
| 48 | + } |
| 49 | + else { |
| 50 | + logger._print ('Graph is DISCONNECTED. Edge IS a bridge'); |
| 51 | + bridges.push ([i,j]); |
| 52 | + } |
| 53 | + } |
| 54 | + } |
| 55 | + } |
| 56 | + |
| 57 | + return bridges; |
| 58 | +} |
| 59 | + |
| 60 | +var bridges = findBridges (G); |
| 61 | + |
| 62 | +logger._print ('The bridges are: '); |
| 63 | +for (var i in bridges) { |
| 64 | + logger._print (bridges [i] [0] + ' to ' + bridges [i] [1]); |
| 65 | +} |
| 66 | +logger._print ('NOTE: A bridge is both ways, i.e., from A to B and from B to A, because this is an Undirected Graph'); |
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