Problem
We are required to write a JavaScript function that takes in the head of a linked list as the first and the only argument.
Our function should return the value stored in the middlemost node of the list. And if there are two middlemost nodes, we should return the second one of them.
For example, if the list is like this:
Input
[4, 6, 8, 9, 1]
Output
const output = 8;
Following is the code:
Example
class Node {
constructor(data) {
this.data = data;
this.next = null;
};
};
class LinkedList {
constructor() {
this.head = null;
this.size = 0;
};
};
LinkedList.prototype.add = function(data) {
const newNode = new Node(data);
let curr;
if(this.head === null) {
this.head = newNode;
} else {
curr = this.head;
while(curr.next) {
curr = curr.next;
}
curr.next = newNode;
};
this.size++;
};
const list = new LinkedList();
list.add(4);
list.add(6);
list.add(8);
list.add(9);
list.add(1);
const findMiddle = (head) => {
let slow = head
let fast = head
while(fast && fast.next) {
slow = slow.next
fast = fast.next.next
}
return slow.data
};
console.log(findMiddle(list.head));Output
8