826单链表

import java.util.Scanner;

public class Main {
    public static int N = 100010;
    public static int head;//头位置
    public static int[] e = new int[N];//值
    public static int[] ne = new int[N];//下个结点位置
    public static int idx;//点用到哪里

     static  {
        head = -1;  // 没有头结点
        idx = 0;    // 没有存入数据
    }

    public static void add_to_head(int x) {
        e[idx] = x;
        ne[idx] = head;
        head = idx;
        idx++;
    }

    public static void add(int k, int x) {
        e[idx] = x;
        ne[idx] = ne[k];
        ne[k] = idx;
        idx++;
    }

    public static void remove(int k) {
        ne[k] = ne[ne[k]];
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int m = sc.nextInt();
        while (m-- != 0) {
            String op = sc.next();
            int k, x;
            if (op.equals("H")) {
                x = sc.nextInt();
                add_to_head(x);
            } else if (op.equals("D")) {
                k = sc.nextInt();
                if (k == 0) {
                    head = ne[head];
                }else
                remove(k - 1);
            } else {
                k = sc.nextInt();
                x = sc.nextInt();
                add(k - 1, x);
            }
        }
        for (int i = head; i != -1; i = ne[i]) {
            System.out.print(e[i]+" ");
        }
        System.out.println();
    }
}