Write a program to complete the following command: new id - create a specified sequence of Numbers for id (id < 200000) Add id num - to join the sequence of Numbers for id integer num merge id1 id2 - merger sequence number of id1 and id2, and make id2 empty unique id - remove repetitive element in the sequence id out id - from small to large, output the elements of sequence of Numbers for ids separated by Spaces Input The First Line is n which mean the number of the Command (n <= 200000). The next n lines are correct Command. You don't have to worry wrong input and id is int. Output Then output according the requirements. Sample Input 16 new 1 new 2 add 1 1 add 1 2 add 1 3 add 2 1 add 2 2 add 2 3 add 2 4 out 1 out 2 merge 1 2 out 1 out 2 unique 1 out 1 16 new 1 new 2 add 1 1 add 1 2 add 1 3 add 2 1 add 2 2 add 2 3 add 2 4 out 1 out 2 merge 1 2 out 1 out 2 unique 1 out 1 ​ Sample Ouput 1 2 3 1 2 3 4 1 1 2 2 3 3 4 1 2 3 4 ​

以下是 Python3 的实现：

from collections import defaultdict

def new(d, id):
    if id not in d:
        d[id] = []

def add(d, id, num):
    d[id].append(num)

def merge(d, id1, id2):
    d[id1] += d[id2]
    d[id2] = []

def unique(d, id):
    d[id] = list(set(d[id]))

def out(d, id):
    print(' '.join(map(str, sorted(d[id]))))

n = int(input())
d = defaultdict(list)
for i in range(n):
    args = input().split()
    if args[0] == 'new':
        new(d, int(args[1]))
    elif args[0] == 'add':
        add(d, int(args[1]), int(args[2]))
    elif args[0] == 'merge':
        merge(d, int(args[1]), int(args[2]))
    elif args[0] == 'unique':
        unique(d, int(args[1]))
    elif args[0] == 'out':
        out(d, int(args[1]))

思路是用 defaultdict 存储每个 id 对应的序列，然后根据命令逐个处理。代码中的 `new`、`add`、`merge`、`unique`、`out` 分别对应题目中的五个命令。