SOURCE

/**
 * 将数组转换为链表
 * @param array arr  需要转换的数组
 * @param int  type  转换的类型，0为单链表，1为循环链表
 * @return object    返回链表
 */
function array2List(arr, type = 0) {
  if (!arr.length) return null;
  let header = { index: 0, data:arr[0], next: null };
  let obj = header;
  for (let i = 1; i < arr.length; i++) {
    obj.next = { index: i, data: arr[i], next: null };
    obj = obj.next;
  }
  if (type) obj.next = header;
  return header;
}

function reverseList (head) {
    let prev = null;
    let curr = head;
    while(curr) {
        const next = curr.next;
        curr.next = prev;
        prev = curr;
        curr = next;
    }
    return prev;
}

console.log(JSON.stringify(findReverseKNode(array2List([1, 2, 3, 7, 8]), 3)))