70 lines
1.5 KiB
JavaScript
70 lines
1.5 KiB
JavaScript
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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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