P15861 [LBA-OI R3 A] A_Step_Back

[](https://www.bilibili.com/video/BV1AJ411c71z/?spm_id_from=333.337.search-card.all.click&vd_source=c312dca0c4478959520831ae9d29cd62)

We use $|p|$ to denote the length of the sequence $p$. Given an integer $m$, you are required to construct a sequence $a$ that satisfies: - For all $1 \le i \le |a|$, $a_i \in [1, 10^6]$. - There are exactly $m$ pairs $(i,j)$ such that $i

A single integer $m$ on a line.

The first line outputs the length $n$ of the sequence. The second line outputs $n$ integers separated by spaces, representing the constructed sequence.

For $100\%$ of the data, $0\le m\le 10^9$. | Subtask ID | $m$ | Special Property | Score | |:-:|:-:|:-:|:-:| | $1$ | $\le 9$ | ✗ | $10$ | | $3$ | $\le 170$ | ✓ | $10$ | | $2$ | $\le 170$ | ✗ | $20$ | | $4$ | $\le 10^5$ | ^ | $20$ | | $5$ | Unrestricted | ✓ | $10$ | | $6$ | ^ | ✗ | $30$ | **Special Property**: There exists a positive integer $n$ such that $$m=\frac{n(n-1)}{2}$$ Additionally, each test case has the following special scoring rule: Let $s$ be the minimal possible length of $a$, and $l$ be the length of your sequence $a$. If the test case is worth $P$ points, you will obtain $$\left\lfloor P\times \frac{\left\lfloor 100\cdot\left(\frac{s+114}{l+114}\right)^{1.14} \right\rfloor}{100} \right\rfloor$$ points. There may be minor differences due to precision issues.