Codeforces Round 767 (Div. 2)
C
Meximum Array
Codeforces
未评级
原题
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Mihai has just learned about the MEX concept and since he liked it so much, he decided to use it right away.

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Given an array $a$ of $n$ non-negative integers, Mihai wants to create a new array $b$ that is formed in the following way:

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While $a$ is not empty:

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  • Choose an integer $k$ ($1 \leq k \leq |a|$).
  • Append the MEX of the first $k$ numbers of the array $a$ to the end of array $b$ and erase them from the array $a$, shifting the positions of the remaining numbers in $a$.
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But, since Mihai loves big arrays as much as the MEX concept, he wants the new array $b$ to be the lexicographically maximum. So, Mihai asks you to tell him what the maximum array $b$ that can be created by constructing the array optimally is.

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An array $x$ is lexicographically greater than an array $y$ if in the first position where $x$ and $y$ differ $x_i \gt y_i$ or if $|x| \gt |y|$ and $y$ is a prefix of $x$ (where $|x|$ denotes the size of the array $x$).

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The MEX of a set of non-negative integers is the minimal non-negative integer such that it is not in the set. For example, MEX({${1, 2, 3}$}) $= 0$ and MEX({${0, 1, 2, 4, 5}$}) $= 3$.

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Input

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The first line of the input contains a single integer $t$ ($1 \le t \le 100$) — the number of test cases. The description of test cases follows.

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The first line of each test case contains a single integer $n$ ($1 \leq n \leq 2 \cdot 10^5$) — the number of elements in the array $a$.

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The second line of each test case contains $n$ non-negative integers $a_1, \ldots, a_n$ ($0 \leq a_i \leq n$), where $a_i$ is the $i$-th integer from the array $a$.

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It is guaranteed that the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$.

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Output

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For each test case print $m$ — the length of the maximum array $b$ Mihai can create, followed by $m$ integers denoting the elements of the array $b$.

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Note

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In the first test case, the lexicographically maximum array $b$ is obtained by selecting $k=5$, resulting in the $MEX$ of the whole array $a$. It is lexicographically maximum because an array starting with a smaller number than $4$ is lexicographically smaller, and choosing a $k \lt 5$ would result in an array starting with a number smaller than $4$.

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In the second test case, there are two ways to obtain the maximum array: first selecting $k=6$, then $k=2$, or first selecting $k=7$ and then $k=1$.

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样例

Input #1
6
5
1 0 2 0 3
8
2 2 3 4 0 1 2 0
1
1
5
0 1 2 3 4
4
0 1 1 0
10
0 0 2 1 1 1 0 0 1 1
Output #1
1
4
2
5 1
1
0
1
5
2
2 2
4
3 2 2 0
InputCopy OutputCopy
题目信息
题号
1629C
时间限制
2 s
内存限制
256 MB

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。