Solution.ts

/**
 * Definition for singly-linked list.
 * class ListNode {
 *     val: number
 *     next: ListNode | null
 *     constructor(val?: number, next?: ListNode | null) {
 *         this.val = (val===undefined ? 0 : val)
 *         this.next = (next===undefined ? null : next)
 *     }
 * }
 */

function numComponents(head: ListNode | null, nums: number[]): number {
    const set = new Set<number>(nums);
    let res = 0;
    let cur = head;
    let inSet = false;
    while (cur != null) {
        if (set.has(cur.val)) {
            if (!inSet) {
                inSet = true;
                res++;
            }
        } else {
            inSet = false;
        }
        cur = cur.next;
    }
    return res;
}