<p>Given a singly linked list, return a random node's value from the linked list. Each node must have the <strong>same probability</strong> of being chosen.</p> <p>Implement the <code>Solution</code> class:</p> <ul> <li><code>Solution(ListNode head)</code> Initializes the object with the head of the singly-linked list <code>head</code>.</li> <li><code>int getRandom()</code> Chooses a node randomly from the list and returns its value. All the nodes of the list should be equally likely to be chosen.</li> </ul> <p> </p> <p><strong>Example 1:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2021/03/16/getrand-linked-list.jpg" style="width: 302px; height: 62px;" /> <pre> <strong>Input</strong> ["Solution", "getRandom", "getRandom", "getRandom", "getRandom", "getRandom"] [[[1, 2, 3]], [], [], [], [], []] <strong>Output</strong> [null, 1, 3, 2, 2, 3] <strong>Explanation</strong> Solution solution = new Solution([1, 2, 3]); solution.getRandom(); // return 1 solution.getRandom(); // return 3 solution.getRandom(); // return 2 solution.getRandom(); // return 2 solution.getRandom(); // return 3 // getRandom() should return either 1, 2, or 3 randomly. Each element should have equal probability of returning. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li>The number of nodes in the linked list will be in the range <code>[1, 10<sup>4</sup>]</code>.</li> <li><code>-10<sup>4</sup> <= Node.val <= 10<sup>4</sup></code></li> <li>At most <code>10<sup>4</sup></code> calls will be made to <code>getRandom</code>.</li> </ul> <p> </p> <p><strong>Follow up:</strong></p> <ul> <li>What if the linked list is extremely large and its length is unknown to you?</li> <li>Could you solve this efficiently without using extra space?</li> </ul>