Find middle element in a linked list
Given a non-empty, singly linked list with head node head
, return a middle node of linked list.
If there are two middle nodes, return the second middle node.
Example 1:
Input: [1,2,3,4,5] Output: Node 3 from this list (Serialization: [3,4,5]) The returned node has value 3. (The judge's serialization of this node is [3,4,5]). Note that we returned a ListNode object ans, such that: ans.val = 3, ans.next.val = 4, ans.next.next.val = 5, and ans.next.next.next = NULL.
Example 2:
Input: [1,2,3,4,5,6] Output: Node 4 from this list (Serialization: [4,5,6]) Since the list has two middle nodes with values 3 and 4, we return the second one.
goli202084 Answered question
Simple solution – traversing through the linked list, collecting elements in an array and returning the middle element of the array
/** * Definition for singly-linked list. * function ListNode(val) { * this.val = val; * this.next = null; * } */ /** * @param {ListNode} head * @return {ListNode} */ var middleNode = function(head) { var arr = []; var currNode = head; while(currNode) { arr.push(currNode) currNode = currNode.next; } var node = (arr.length % 2 === 0) ? arr[arr.length/2] : arr[Math.round(arr.length/2)-1]; return node; };
goli202084 Answered question