All Ancestors of a Node in a Directed Acyclic Graph LeetCode solution in JavaScript

1
var getAncestors = function (n, edges) {
2
  const adj = [];
3
  const ancestors = [];
4
  const inDegrees = new Array(n).fill(0);
5

6
  for (let i = 0; i < n; ++i) {
7
    adj[i] = new Set();
8
    ancestors[i] = new Set();
9
  }
10

11
  for (const [from, to] of edges) {
12
    adj[from].add(to);
13
    ++inDegrees[to];
14
  }
15

16
  const queue = [];
17

18
  for (let i = 0; i < n; ++i) {
19
    if (inDegrees[i] === 0) queue.push(i);
20
  }
21

22
  while (queue.length > 0) {
23
    const node = queue.shift();
24

25
    for (const child of adj[node]) {
26
      --inDegrees[child];
27

28
      if (inDegrees[child] === 0) queue.push(child);
29

30
      ancestors[child].add(node);
31
      ancestors[node].forEach((prev) => ancestors[child].add(prev));
32
    }
33
  }
34

35
  const res = [];
36

37
  for (let i = 0; i < n; ++i) {
38
    res[i] = [...ancestors[i]].sort((a, b) => a - b);
39
  }
40

41
  return res;
42
};