monaco-editor
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A browser based code editor
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JavaScript
/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
class DirectedGraph {
constructor() {
this._nodes = new Set();
this._outgoingEdges = new Map();
}
static from(nodes, getOutgoing) {
const graph = new DirectedGraph();
for (const node of nodes) {
graph._nodes.add(node);
}
for (const node of nodes) {
const outgoing = getOutgoing(node);
if (outgoing.length > 0) {
const outgoingSet = new Set();
for (const target of outgoing) {
outgoingSet.add(target);
}
graph._outgoingEdges.set(node, outgoingSet);
}
}
return graph;
}
/**
* After this, the graph is guaranteed to have no cycles.
*/
removeCycles() {
const foundCycles = [];
const visited = new Set();
const recursionStack = new Set();
const toRemove = [];
const dfs = (node) => {
visited.add(node);
recursionStack.add(node);
const outgoing = this._outgoingEdges.get(node);
if (outgoing) {
for (const neighbor of outgoing) {
if (!visited.has(neighbor)) {
dfs(neighbor);
}
else if (recursionStack.has(neighbor)) {
// Found a cycle
foundCycles.push(neighbor);
toRemove.push({ from: node, to: neighbor });
}
}
}
recursionStack.delete(node);
};
// Run DFS from all unvisited nodes
for (const node of this._nodes) {
if (!visited.has(node)) {
dfs(node);
}
}
// Remove edges that cause cycles
for (const { from, to } of toRemove) {
const outgoingSet = this._outgoingEdges.get(from);
if (outgoingSet) {
outgoingSet.delete(to);
}
}
return { foundCycles };
}
getOutgoing(node) {
const outgoing = this._outgoingEdges.get(node);
return outgoing ? Array.from(outgoing) : [];
}
}
export { DirectedGraph };