Leetcode - 61. Rotate List

#leetcode

🔄 Approach:

Calculate the length of the list.
Connect the tail to the head to make it circular.
Find the new tail at position (length - k % length).
Break the circle after the new tail and return the new head.

💻 Code:

var rotateRight = function(head, k) {
    if (!head || !head.next || k === 0) return head;

    // Step 1: Calculate length and get tail node
    let curr = head;
    let len = 1;
    while (curr.next) {
        curr = curr.next;
        len++;
    }

    // Step 2: Make it a circular list
    curr.next = head;

    // Step 3: Calculate the new tail position
    let times = len - (k % len);
    let curr2 = head;
    for (let i = 1; i < times; i++) {
        curr2 = curr2.next;
    }

    // Step 4: Break the loop and return new head
    let newHead = curr2.next;
    curr2.next = null;

    return newHead;
};