Problem:
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->3
G = [0, 1, 3]
Output: 2
Explanation:
0 and 1 are connected, so [0, 1] and [3] are the two connected components.
Example 2:
Input:
head: 0->1->2->3->4
G = [0, 3, 1, 4]
Output: 2
Explanation:
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.
思路：
Solution (C++):
int numComponents(ListNode* head, vector<int>& G) {
unordered_set<int> set_G(G.begin(), G.end());
int res = 0;
while (head) {
if (set_G.count(head->val) && (!(head->next) || !set_G.count(head->next->val))) ++ res;
head = head->next;
}
return res;
}
性能：
Runtime: 44 ms Memory Usage: 12.5 MB
思路：
Solution (C++):
性能：
Runtime: ms Memory Usage: MB
