817

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    int numComponents(ListNode* head, vector<int>& G) {
        bool vis[100001] = {0};
        for(auto i: G) vis[i] = 1;
        int res = 0;
        while(head){
            if(vis[head->val] && (!head->next || !vis[head->next->val])) res++;
            head = head->next;
        }
        return res;
    }
};