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69 lines
1.5 KiB
69 lines
1.5 KiB
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/** |
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* Topological sorting function |
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* |
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* @param {Array} edges |
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* @returns {Array} |
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*/ |
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module.exports = function(edges){ |
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return toposort(uniqueNodes(edges), edges) |
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} |
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module.exports.array = toposort |
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function toposort(nodes, edges) { |
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var cursor = nodes.length |
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, sorted = new Array(cursor) |
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, visited = {} |
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, i = cursor |
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while (i--) { |
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if (!visited[i]) visit(nodes[i], i, []) |
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} |
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return sorted |
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function visit(node, i, predecessors) { |
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if(predecessors.indexOf(node) >= 0) { |
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var nodeRep |
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try { |
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nodeRep = ", node was:" + JSON.stringify(node) |
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} catch(e) { |
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nodeRep = "" |
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} |
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throw new Error('Cyclic dependency' + nodeRep) |
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} |
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if (!~nodes.indexOf(node)) { |
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throw new Error('Found unknown node. Make sure to provided all involved nodes. Unknown node: '+JSON.stringify(node)) |
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} |
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if (visited[i]) return; |
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visited[i] = true |
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// outgoing edges |
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var outgoing = edges.filter(function(edge){ |
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return edge[0] === node |
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}) |
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if (i = outgoing.length) { |
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var preds = predecessors.concat(node) |
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do { |
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var child = outgoing[--i][1] |
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visit(child, nodes.indexOf(child), preds) |
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} while (i) |
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} |
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sorted[--cursor] = node |
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} |
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} |
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function uniqueNodes(arr){ |
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var res = [] |
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for (var i = 0, len = arr.length; i < len; i++) { |
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var edge = arr[i] |
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if (res.indexOf(edge[0]) < 0) res.push(edge[0]) |
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if (res.indexOf(edge[1]) < 0) res.push(edge[1]) |
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} |
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return res |
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}
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