Codeforces Round 796 (Div. 1) |
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Finished |
Shinmyoumaru has a mallet that can turn objects bigger or smaller. She is testing it out on a sequence $$$a$$$ and a number $$$v$$$ whose initial value is $$$1$$$. She wants to make $$$v = \gcd\limits_{i\ne j}\{a_i\cdot a_j\}$$$ by no more than $$$10^5$$$ operations ($$$\gcd\limits_{i\ne j}\{a_i\cdot a_j\}$$$ denotes the $$$\gcd$$$ of all products of two distinct elements of the sequence $$$a$$$).
In each operation, she picks a subsequence $$$b$$$ of $$$a$$$, and does one of the followings:
Note that she does not need to guarantee that $$$v$$$ is an integer, that is, $$$v$$$ does not need to be a multiple of $$$\mathrm{lcm}(b)$$$ when performing Reduce.
Moreover, she wants to guarantee that the total length of $$$b$$$ chosen over the operations does not exceed $$$10^6$$$. Fine a possible operation sequence for her. You don't need to minimize anything.
The first line contains a single integer $$$n$$$ ($$$2\leq n\leq 10^5$$$) — the size of sequence $$$a$$$.
The second line contains $$$n$$$ integers $$$a_1,a_2,\cdots,a_n$$$ ($$$1\leq a_i\leq 10^6$$$) — the sequence $$$a$$$.
It can be shown that the answer exists.
The first line contains a non-negative integer $$$k$$$ ($$$0\leq k\leq 10^5$$$) — the number of operations.
The following $$$k$$$ lines contains several integers. For each line, the first two integers $$$f$$$ ($$$f\in\{0,1\}$$$) and $$$p$$$ ($$$1\le p\le n$$$) stand for the option you choose ($$$0$$$ for Enlarge and $$$1$$$ for Reduce) and the length of $$$b$$$. The other $$$p$$$ integers of the line $$$i_1,i_2,\ldots,i_p$$$ ($$$1\le i_1<i_2<\ldots<i_p\le n$$$) represents the indexes of the subsequence. Formally, $$$b_j=a_{i_j}$$$.
3 6 10 15
1 0 3 1 2 3
4 2 4 8 16
2 0 1 4 1 1 1
Test case 1:
$$$\gcd\limits_{i\ne j}\{a_i\cdot a_j\}=\gcd\{60,90,150\}=30$$$.
Perform $$$v = v\cdot \operatorname{lcm}\{a_1,a_2,a_3\}=30$$$.
Test case 2:
$$$\gcd\limits_{i\ne j}\{a_i\cdot a_j\}=8$$$.
Perform $$$v = v\cdot \operatorname{lcm}\{a_4\}=16$$$.
Perform $$$v = \frac{v}{\operatorname{lcm}\{a_1\}}=8$$$.
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