We are given head, the head node of a linked list containing unique integer values.

We are also given the list G, a subset of the values in the linked list.

Return the number of connected components in G, where two values are connected if they appear consecutively in the linked list.

Example 1:

Input: head: 0->1->2->3G = [0, 1, 3]Output: 2Explanation: 0 and 1 are connected, so [0, 1] and [3] are the two connected components.

Example 2:

Input: head: 0->1->2->3->4G = [0, 3, 1, 4]Output: 2Explanation: 0 and 1 are connected, 3 and 4 are connected, so [0, 1] and [3, 4] are the two connected components.

Note:

• If N is the length of the linked list given by head, 1 <= N <= 10000.
• The value of each node in the linked list will be in the range [0, N - 1].
• 1 <= G.length <= 10000.
• G is a subset of all values in the linked list.

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1 /** 2  * Definition for singly-linked list. 3  * struct ListNode { 4  *     int val; 5  *     ListNode *next; 6  *     ListNode(int x) : val(x), next(NULL) {} 7  * }; 8  */ 9 class Solution {10 public:11     int numComponents(ListNode* head, vector
     
      & G) {12         unordered_set
      
        set;13         for(int num: G){14             set.insert(num);15         }16         17         int count = 0;18         bool prev = false;19         ListNode* curr = head;20         while(curr){21             if(set.find(curr->val)!=set.end()){22                 if(!prev){23                     count++;24                     prev = true;25                 }26             }else{27                 prev = false;28             }29             30             curr= curr->next;31         }32         return count;33     }34 };