Find the Minimum and Maximum Number of Nodes Between Critical Points LeetCode solution in JavaScript

1
var nodesBetweenCriticalPoints = function (head) {
2
  const MAX = Number.MAX_SAFE_INTEGER;
3
  const MIN = Number.MIN_SAFE_INTEGER;
4

5
  let currNode = head.next;
6
  let prevVal = head.val;
7

8
  let minIdx = MAX;
9
  let maxIdx = MIN;
10

11
  let minDist = MAX;
12
  let maxDist = MIN;
13

14
  for (let i = 1; currNode.next != null; ++i) {
15
    const currVal = currNode.val;
16
    const nextNode = currNode.next;
17
    const nextVal = nextNode.val;
18

19
    // Triggers when we have either a maxima or a minima
20
    if (
21
      (prevVal < currVal && currVal > nextVal) ||
22
      (prevVal > currVal && currVal < nextVal)
23
    ) {
24
      if (maxIdx != MIN) minDist = Math.min(minDist, i - maxIdx);
25
      if (minIdx != MAX) maxDist = Math.max(maxDist, i - minIdx);
26

27
      if (minIdx == MAX) minIdx = i;
28
      maxIdx = i;
29
    }
30

31
    prevVal = currVal;
32
    currNode = nextNode;
33
  }
34

35
  const minRes = minDist === MAX ? -1 : minDist;
36
  const maxRes = maxDist === MIN ? -1 : maxDist;
37

38
  return [minRes, maxRes];
39
};