Anjan Dutta

Leet Code 876: Middle of the Linked List

Problem statement:

Given the head of a singly linked list, return the middle node of the linked list.

If there are two middle nodes, return the second middle node.

Constraints:

The number of nodes in the list is in the range [1, 100].
1 <= Node.val <= 100

Solution:

/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} head
 * @return {ListNode}
 */
var middleNode = function(head) {
    let len = 1, index = 1;
    let temp = head;
    let arr = [];
    while(head.next!=null) {
        len++;
        head = head.next;
    }
    let mid = Math.ceil(len/2); 
    if(len%2==0) {
        mid++;
    }
    while(mid>index) {
        temp = temp.next;
        index++;
    }
    return temp;
};