Codeforces Round 554 (Div. 2)
B
Neko Performs Cat Furrier Transform
Codeforces
1300
原题
← AC →
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Cat Furrier Transform is a popular algorithm among cat programmers to create longcats. As one of the greatest cat programmers ever exist, Neko wants to utilize this algorithm to create the perfect longcat.

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Assume that we have a cat with a number $x$. A perfect longcat is a cat with a number equal $2^m - 1$ for some non-negative integer $m$. For example, the numbers $0$, $1$, $3$, $7$, $15$ and so on are suitable for the perfect longcats.

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In the Cat Furrier Transform, the following operations can be performed on $x$:

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  • (Operation A): you select any non-negative integer $n$ and replace $x$ with $x \oplus (2^n - 1)$, with $\oplus$ being a bitwise XOR operator.
  • (Operation B): replace $x$ with $x + 1$.
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The first applied operation must be of type A, the second of type B, the third of type A again, and so on. Formally, if we number operations from one in the order they are executed, then odd-numbered operations must be of type A and the even-numbered operations must be of type B.

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Neko wants to produce perfect longcats at industrial scale, thus for each cat Neko only wants to perform at most $40$ operations. Can you help Neko writing a transformation plan?

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Note that it is not required to minimize the number of operations. You just need to use no more than $40$ operations.

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Input

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The only line contains a single integer $x$ ($1 \le x \le 10^6$).

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Output

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The first line should contain a single integer $t$ ($0 \le t \le 40$) — the number of operations to apply.

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Then for each odd-numbered operation print the corresponding number $n_i$ in it. That is, print $\lceil \frac{t}{2} \rceil$ integers $n_i$ ($0 \le n_i \le 30$), denoting the replacement $x$ with $x \oplus (2^{n_i} - 1)$ in the corresponding step.

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If there are multiple possible answers, you can print any of them. It is possible to show, that there is at least one answer in the constraints of this problem.

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Note

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In the first test, one of the transforms might be as follows: $39 \to 56 \to 57 \to 62 \to 63$. Or more precisely:

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  1. Pick $n = 5$. $x$ is transformed into $39 \oplus 31$, or $56$.
  2. Increase $x$ by $1$, changing its value to $57$.
  3. Pick $n = 3$. $x$ is transformed into $57 \oplus 7$, or $62$.
  4. Increase $x$ by $1$, changing its value to $63 = 2^6 - 1$.
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In the second and third test, the number already satisfies the goal requirement.

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样例

Input #1
39
Output #1
4
5 3
InputCopy OutputCopy
Input #2
1
Output #2
0
InputCopy OutputCopy
Input #3
7
Output #3
0
InputCopy OutputCopy
题目信息
题号
1152B
时间限制
1 s
内存限制
256 MB
标签
位运算
构造
DFS 及类似
数学

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。