题解 | #从单向链表中删除指定值的节点#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int n = in.nextInt();
            int headVal = in.nextInt();
            // 创建带虚头节点的链表
            Node head = new Node(0);
            Node firstNode = new Node(headVal);
            head.next = firstNode;
            for (int i = 0; i < n - 1; i++) {
                // 当前节点值
                int curVal = in.nextInt();
                Node curNode = new Node(curVal);
                // 前一个节点值
                int preVal = in.nextInt();
                // 查找前一个节点值的父节点,插入需要找到待插入节点的父节点
                Node preNode = findPreNodeByVal(head, preVal).next;
                // 将当前节点值插入到其之后
                Node temp = preNode.next;
                curNode.next = temp;
                preNode.next = curNode;
            }

            // 删除的结点的值
            // 删除需要找到待删除节点的父节点
            int toDeleteNodeVal = in.nextInt();
            Node preNode = findPreNodeByVal(head, toDeleteNodeVal);
            preNode.next = preNode.next.next;

            while (head.next != null) {
                System.out.print(head.next.val + " ");
                head = head.next;
            }
        }
    }


    // 根据值查找其前一个节点
    private static Node findPreNodeByVal(Node head, int val) {
        if (head.next == null) {
            return head;
        }

        Node curNode = head;
        while (curNode.next != null) {
            if (curNode.next.val == val) {
                return curNode;
            }
            curNode = curNode.next;
        }
        return head;
    }


}


class Node {
    int val;
    Node next;
    public Node(int val) {
        this.val = val;
    }
}