Codeforces Round 720 (Div. 2) |
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Finished |
Nastia has received an array of $$$n$$$ positive integers as a gift.
She calls such an array $$$a$$$ good that for all $$$i$$$ ($$$2 \le i \le n$$$) takes place $$$gcd(a_{i - 1}, a_{i}) = 1$$$, where $$$gcd(u, v)$$$ denotes the greatest common divisor (GCD) of integers $$$u$$$ and $$$v$$$.
You can perform the operation: select two different indices $$$i, j$$$ ($$$1 \le i, j \le n$$$, $$$i \neq j$$$) and two integers $$$x, y$$$ ($$$1 \le x, y \le 2 \cdot 10^9$$$) so that $$$\min{(a_i, a_j)} = \min{(x, y)}$$$. Then change $$$a_i$$$ to $$$x$$$ and $$$a_j$$$ to $$$y$$$.
The girl asks you to make the array good using at most $$$n$$$ operations.
It can be proven that this is always possible.
The first line contains a single integer $$$t$$$ ($$$1 \le t \le 10\,000$$$) — the number of test cases.
The first line of each test case contains a single integer $$$n$$$ ($$$1 \le n \le 10^5$$$) — the length of the array.
The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_{n}$$$ ($$$1 \le a_i \le 10^9$$$) — the array which Nastia has received as a gift.
It's guaranteed that the sum of $$$n$$$ in one test doesn't exceed $$$2 \cdot 10^5$$$.
For each of $$$t$$$ test cases print a single integer $$$k$$$ ($$$0 \le k \le n$$$) — the number of operations. You don't need to minimize this number.
In each of the next $$$k$$$ lines print $$$4$$$ integers $$$i$$$, $$$j$$$, $$$x$$$, $$$y$$$ ($$$1 \le i \neq j \le n$$$, $$$1 \le x, y \le 2 \cdot 10^9$$$) so that $$$\min{(a_i, a_j)} = \min{(x, y)}$$$ — in this manner you replace $$$a_i$$$ with $$$x$$$ and $$$a_j$$$ with $$$y$$$.
If there are multiple answers, print any.
2 5 9 6 3 11 15 3 7 5 13
2 1 5 11 9 2 5 7 6 0
Consider the first test case.
Initially $$$a = [9, 6, 3, 11, 15]$$$.
In the first operation replace $$$a_1$$$ with $$$11$$$ and $$$a_5$$$ with $$$9$$$. It's valid, because $$$\min{(a_1, a_5)} = \min{(11, 9)} = 9$$$.
After this $$$a = [11, 6, 3, 11, 9]$$$.
In the second operation replace $$$a_2$$$ with $$$7$$$ and $$$a_5$$$ with $$$6$$$. It's valid, because $$$\min{(a_2, a_5)} = \min{(7, 6)} = 6$$$.
After this $$$a = [11, 7, 3, 11, 6]$$$ — a good array.
In the second test case, the initial array is already good.
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