1
var splitListToParts = function (head, k) {
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  let length = 0,
3
    current = head,
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    parts = [];
5

6
  while (current) {
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    length++;
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    current = current.next;
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  }
10

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  let base_size = Math.floor(length / k),
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    extra = length % k;
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  current = head;
14

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  for (let i = 0; i < k; i++) {
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    let part_size = base_size + (extra > 0 ? 1 : 0);
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    let part_head = null,
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      part_tail = null;
19

20
    for (let j = 0; j < part_size; j++) {
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      if (!part_head) {
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        part_head = part_tail = current;
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      } else {
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        part_tail.next = current;
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        part_tail = part_tail.next;
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      }
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28
      if (current) {
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        current = current.next;
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      }
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    }
32

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    if (part_tail) {
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      part_tail.next = null;
35
    }
36

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    parts.push(part_head);
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    extra = Math.max(extra - 1, 0);
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  }
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41
  return parts;
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};