From 0925eb622a91bd988d7bcf7604fdeed56a55bb69 Mon Sep 17 00:00:00 2001 From: Flavio De Stefano Date: Sun, 4 Jun 2017 14:33:23 +0200 Subject: [PATCH] Added BFS bipartiteness algorithm AKA: Graph is 2-colorable. --- algorithm/graph_search/bfs/desc.json | 3 +- .../bfs/test_bipartiteness/code.js | 41 +++++++++++++++++++ .../bfs/test_bipartiteness/data.js | 14 +++++++ 3 files changed, 57 insertions(+), 1 deletion(-) create mode 100644 algorithm/graph_search/bfs/test_bipartiteness/code.js create mode 100644 algorithm/graph_search/bfs/test_bipartiteness/data.js diff --git a/algorithm/graph_search/bfs/desc.json b/algorithm/graph_search/bfs/desc.json index 743e0c98..0e39e3cb 100644 --- a/algorithm/graph_search/bfs/desc.json +++ b/algorithm/graph_search/bfs/desc.json @@ -18,6 +18,7 @@ ], "files": { "tree": "Searching a tree", - "shortest_path": "Finding the shortest path" + "shortest_path": "Finding the shortest path", + "test_bipartiteness": "Test if graph is biparted (or 2-colorable)" } } diff --git a/algorithm/graph_search/bfs/test_bipartiteness/code.js b/algorithm/graph_search/bfs/test_bipartiteness/code.js new file mode 100644 index 00000000..da6484e8 --- /dev/null +++ b/algorithm/graph_search/bfs/test_bipartiteness/code.js @@ -0,0 +1,41 @@ +function BFSCheckBipartiteness(s) { + var Q = []; + + // Create a new matrix to set colors (0,1) + var Colors = []; + for (var _i = 0; _i < G.length; _i++) Colors[_i] = -1; + colorsTracer._setData(Colors); + + Colors[s] = 1; + colorsTracer._notify(s, 1); + + Q.push(s); // add start node to queue + + while (Q.length > 0) { + var node = Q.shift(); // dequeue + tracer._visit(node)._wait(); + + for (var i = 0; i < G[node].length; i++) { + if (G[node][i]) { + + if (Colors[i] === -1) { + + Colors[i] = 1 - Colors[node]; + colorsTracer._notify(i, 1 - Colors[node]); + + Q.push(i); + tracer._visit(i, node)._wait(); + + } else if (Colors[i] == Colors[node]) { + logger._print('Graph is not biparted'); + return false; + } + } + } + } + + logger._print('Graph is biparted'); + return true; +} + +BFSCheckBipartiteness(0); \ No newline at end of file diff --git a/algorithm/graph_search/bfs/test_bipartiteness/data.js b/algorithm/graph_search/bfs/test_bipartiteness/data.js new file mode 100644 index 00000000..36835cd7 --- /dev/null +++ b/algorithm/graph_search/bfs/test_bipartiteness/data.js @@ -0,0 +1,14 @@ +var tracer = new UndirectedGraphTracer(); +var logger = new LogTracer(); +tracer.attach(logger); + +var G =[ +[0, 1, 0, 1, 1], +[1, 0, 1, 0, 0], +[0, 1, 0, 1, 0], +[1, 0, 1, 0, 0], // <-- replace latest 0 with 1 to make G not biparted +[1, 0, 0, 0, 0], +]; +tracer._setData(G, 0); + +var colorsTracer = new Array1DTracer('Colors'); \ No newline at end of file pFad - Phonifier reborn

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