43 lines
1.1 KiB
JavaScript
43 lines
1.1 KiB
JavaScript
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var _ = require("../lodash");
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module.exports = dfs;
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/*
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* A helper that preforms a pre- or post-order traversal on the input graph
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* and returns the nodes in the order they were visited. If the graph is
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* undirected then this algorithm will navigate using neighbors. If the graph
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* is directed then this algorithm will navigate using successors.
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*
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* Order must be one of "pre" or "post".
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*/
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function dfs(g, vs, order) {
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if (!_.isArray(vs)) {
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vs = [vs];
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}
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var navigation = (g.isDirected() ? g.successors : g.neighbors).bind(g);
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var acc = [];
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var visited = {};
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_.each(vs, function(v) {
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if (!g.hasNode(v)) {
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throw new Error("Graph does not have node: " + v);
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}
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doDfs(g, v, order === "post", visited, navigation, acc);
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});
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return acc;
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}
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function doDfs(g, v, postorder, visited, navigation, acc) {
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if (!_.has(visited, v)) {
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visited[v] = true;
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if (!postorder) { acc.push(v); }
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_.each(navigation(v), function(w) {
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doDfs(g, w, postorder, visited, navigation, acc);
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});
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if (postorder) { acc.push(v); }
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}
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}
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