817.链表组件.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/*
 * @lc app=leetcode.cn id=817 lang=java
 *
 * [817] 链表组件
 */

// @lc code=start
/**
 * Definition for singly-linked list.
 * public class ListNode {
 * int val;
 * ListNode next;
 * ListNode() {}
 * ListNode(int val) { this.val = val; }
 * ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public int numComponents(ListNode head, int[] nums) {
        Set<Integer> set = new HashSet<>(Arrays.stream(nums).boxed().collect(Collectors.toList()));
        int res = 0;
        ListNode p = head;

        boolean start = false;
        while (p != null) {
            if (set.contains(p.val)) {
                if (start == false) {
                    start = true;
                    res++;
                }
            } else {
                start = false;
            }
            p = p.next;
        }

        return res;
    }
}
// @lc code=end