版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/u013325815/article/details/85242210
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 byhead
,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:loop一遍,然后用flag来标记之前是否找到,然后count一下即可。这题没有什么意义。
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
class Solution {
public int numComponents(ListNode head, int[] G) {
Set<Integer> hashset = new HashSet<Integer>();
for(Integer i: G){
hashset.add(i);
}
int count = 0;
ListNode cur =head;
boolean found = false;
while(cur != null) {
if(hashset.contains(cur.val)){
if(!found){
found = true;
count++;
}else {
cur = cur.next;
}
} else {
found = false;
cur = cur.next;
}
}
return count;
}
}