Codeforces Global Round 11
F
Boring Card Game
Codeforces
3200
原题
← EG →
翻译中…

When they are bored, Federico and Giada often play the following card game with a deck containing $6n$ cards.

翻译中…

Each card contains one number between $1$ and $6n$ and each number appears on exactly one card. Initially the deck is sorted, so the first card contains the number $1$, the second card contains the number $2$, $\dots$, and the last one contains the number $6n$.

翻译中…

Federico and Giada take turns, alternating; Federico starts.

翻译中…

In his turn, the player takes $3$ contiguous cards from the deck and puts them in his pocket. The order of the cards remaining in the deck is not changed. They play until the deck is empty (after exactly $2n$ turns). At the end of the game both Federico and Giada have $3n$ cards in their pockets.

翻译中…

You are given the cards in Federico's pocket at the end of the game. Describe a sequence of moves that produces that set of cards in Federico's pocket.

翻译中…

Input

翻译中…

The first line of the input contains one integer $n$ ($1\le n \le 200$).

翻译中…

The second line of the input contains $3n$ numbers $x_1, x_2,\ldots, x_{3n}$ ($1 \le x_1 \lt x_2 \lt \ldots \lt x_{3n} \le 6n$) – the cards in Federico's pocket at the end of the game.

翻译中…

It is guaranteed that for each test there is at least one sequence of moves that produces such set of cards in Federico's pocket.

翻译中…

Output

翻译中…

Print $2n$ lines, each containing $3$ integers.

翻译中…

The $i$-th line should contain, in increasing order, the integers $a_i \lt b_i \lt c_i$ written on the three cards taken by the player during the $i$-th turn (so taken by Federico if $i$ is odd and by Giada if $i$ is even).

翻译中…

If there is more than one possible sequence of moves, you can print any.

翻译中…

Note

翻译中…

Explanation of the first testcase: Initially the deck has $12 = 2\cdot 6$ sorted cards, so the deck is $[1\ 2\ 3\ 4\ 5\ 6\ 7\ 8\ 9\ 10\ 11\ 12]$.

翻译中…
  • During turn $1$, Federico takes the three cards $[9\ 10\ 11]$. After his move, the deck is $[1\ 2\ 3\ 4\ 5\ 6\ 7\ 8\ 12]$.
  • During turn $2$, Giada takes the three cards $[6\ 7\ 8]$. After her move, the deck is $[1\ 2\ 3\ 4\ 5\ 12]$.
  • During turn $3$, Federico takes the three cards $[2\ 3\ 4]$. After his move, the deck is $[1\ 5\ 12]$.
  • During turn $4$, Giada takes the three cards $[1\ 5\ 12]$. After her move, the deck is empty.
翻译中…

At the end of the game, the cards in Federico's pocket are $[2\ 3\ 4\ 9\ 10\ 11]$ and the cards in Giada's pocket are $[1\ 5\ 6\ 7\ 8\ 12]$.

翻译中…

样例

Input #1
2
2 3 4 9 10 11
Output #1
9 10 11
6 7 8
2 3 4
1 5 12
InputCopy OutputCopy
Input #2
5
1 2 3 4 5 9 11 12 13 18 19 20 21 22 23
Output #2
19 20 21
24 25 26
11 12 13
27 28 29
1 2 3
14 15 16
18 22 23
6 7 8
4 5 9
10 17 30
InputCopy OutputCopy
题目信息
题号
1427F
时间限制
1 s
内存限制
256 MB
标签
数据结构
贪心
树

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。