113 lines
2.4 KiB
JavaScript
113 lines
2.4 KiB
JavaScript
/**
|
|
* general topological sort
|
|
* from https://gist.github.com/1232505
|
|
* @author SHIN Suzuki (shinout310@gmail.com)
|
|
* @param Array<Array> edges : list of edges. each edge forms Array<ID,ID> e.g. [12 , 3]
|
|
*
|
|
* @returns Array : topological sorted list of IDs
|
|
**/
|
|
|
|
function tsort(edges) {
|
|
var nodes = {}, // hash: stringified id of the node => { id: id, afters: lisf of ids }
|
|
sorted = [], // sorted list of IDs ( returned value )
|
|
visited = {}; // hash: id of already visited node => true
|
|
|
|
var Node = function(id) {
|
|
this.id = id;
|
|
this.afters = [];
|
|
}
|
|
|
|
// 1. build data structures
|
|
edges.forEach(function(v) {
|
|
var from = v[0], to = v[1];
|
|
if (!nodes[from]) nodes[from] = new Node(from);
|
|
if (!nodes[to]) nodes[to] = new Node(to);
|
|
nodes[from].afters.push(to);
|
|
});
|
|
|
|
// 2. topological sort
|
|
Object.keys(nodes).forEach(function visit(idstr, ancestors) {
|
|
var node = nodes[idstr],
|
|
id = node.id;
|
|
|
|
// if already exists, do nothing
|
|
if (visited[idstr]) return;
|
|
|
|
if (!Array.isArray(ancestors)) ancestors = [];
|
|
|
|
ancestors.push(id);
|
|
|
|
visited[idstr] = true;
|
|
|
|
node.afters.forEach(function(afterID) {
|
|
if (ancestors.indexOf(afterID) >= 0) // if already in ancestors, a closed chain exists.
|
|
throw new Error('closed chain : ' + afterID + ' is in ' + id);
|
|
|
|
visit(afterID.toString(), ancestors.map(function(v) { return v })); // recursive call
|
|
});
|
|
|
|
sorted.unshift(id);
|
|
});
|
|
|
|
return sorted;
|
|
}
|
|
|
|
/**
|
|
* TEST
|
|
**/
|
|
function tsortTest() {
|
|
|
|
// example 1: success
|
|
var edges = [
|
|
[1, 2],
|
|
[1, 3],
|
|
[2, 4],
|
|
[3, 4]
|
|
];
|
|
|
|
var sorted = tsort(edges);
|
|
console.log(sorted);
|
|
|
|
// example 2: failure ( A > B > C > A )
|
|
edges = [
|
|
['A', 'B'],
|
|
['B', 'C'],
|
|
['C', 'A']
|
|
];
|
|
|
|
try {
|
|
sorted = tsort(edges);
|
|
}
|
|
catch (e) {
|
|
console.log(e.message);
|
|
}
|
|
|
|
// example 3: generate random edges
|
|
var max = 100, iteration = 30;
|
|
function randomInt(max) {
|
|
return Math.floor(Math.random() * max) + 1;
|
|
}
|
|
|
|
edges = (function() {
|
|
var ret = [], i = 0;
|
|
while (i++ < iteration) ret.push( [randomInt(max), randomInt(max)] );
|
|
return ret;
|
|
})();
|
|
|
|
try {
|
|
sorted = tsort(edges);
|
|
console.log("succeeded", sorted);
|
|
}
|
|
catch (e) {
|
|
console.log("failed", e.message);
|
|
}
|
|
|
|
}
|
|
|
|
|
|
// for node.js
|
|
if (typeof exports == 'object' && exports === this) {
|
|
module.exports = tsort;
|
|
if (process.argv[1] === __filename) tsortTest();
|
|
}
|