Create 2192-all-ancestors-of-a-node-in-a-directed-acyclic-graph.js

Author: everthis

2192-all-ancestors-of-a-node-in-a-directed-acyclic-graph.js

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+/**
+ * @param {number} n
+ * @param {number[][]} edges
+ * @return {number[][]}
+ */
+const getAncestors = function(n, edges) {
+  const res = Array.from({ length: n }, () => new Set())
+  const inDegree = Array(n).fill(0)
+  const graph = {}
+  
+  for(const [u, v] of edges) {
+    if(graph[v] == null) graph[v] = []
+    graph[v].push(u)
+    inDegree[v]++
+  }
+  
+  const visited = Array(n).fill(false)
+  for (let i = 0; i < n; i++) {
+    if (!visited[i]) dfs(i);
+  }
+
+  return res.map(set => Array.from(set).sort((a, b) => a - b))
+  
+  function dfs(i) {
+    visited[i] = true
+    for(const p of (graph[i] || [])) {
+      if(visited[p] === false) dfs(p)
+      res[i].add(p)
+      for(const e of res[p]) res[i].add(e)
+    }
+  }
+};