題意

題解

手動做連結串列模擬

#include<cstdio>
#include<iostream>
#include<vector>
using namespace std;
const int MAXN = 2e5;
struct Car {
	int front, back;
}tr[MAXN];

int vec[MAXN];
int main() {
	int n, q;
	scanf("%d%d", &n, &q);

	for (int i = 1; i <= q; i++) {
		int opt;
		scanf("%d", &opt);
		if (opt == 1) {
			int x, y;
			scanf("%d%d", &x, &y);
			tr[y].front = x;
			tr[x].back = y;
		}
		if (opt == 2) {
			int x, y;
			scanf("%d%d", &x, &y);
			tr[y].front = 0;
			tr[x].back = 0;
		}
		if (opt == 3) {
			int x;
			scanf("%d", &x);
			int front = x;
			while (tr[front].front != 0)front = tr[front].front;
			int num = 0;

			vec[++num] = front;
			while (tr[front].back != 0) {
				vec[++num] = tr[front].back;
				front = tr[front].back;
			}
			printf("%d ", num);
			for (int i = 1; i <= num; i++) {
				printf("%d ", vec[i]);
			}
			printf("\n");
		}
	}


	return 0;
}