1
var numOfMinutes = function (n, headID, manager, informTime) {
2
  // Build the tree structure
3
  let tree = {};
4

5
  // {manager: direct employee}
6
  for (let i = 0; i < manager.length; i++) {
7
    // the head of the company does not have a manager
8
    if (i === headID) {
9
      continue;
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    }
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    let m = manager[i];
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    if (!tree[m]) {
13
      tree[m] = [];
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    }
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    tree[m].push(i);
16
  }
17

18
  // BFS
19
  // [employee, time to inform the head]
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  let queue = [[headID, 0]];
21
  let res = 0;
22

23
  while (queue.length) {
24
    let [emp, currTime] = queue.shift();
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    let children = tree[emp] || [];
26
    for (let child of children) {
27
      res = Math.max(res, informTime[emp] + currTime);
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      queue.push([child, informTime[emp] + currTime]);
29
    }
30
  }
31

32
  return res;
33
};