Codeforces Round 866 (Div. 1)
A
Constructive Problem
Codeforces
1300
原题
←B →
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As you know, any problem that does not require the use of complex data structures is considered constructive. You are offered to solve one of such problems.

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You are given an array $a$ of $n$ non-negative integers. You are allowed to perform the following operation exactly once: choose some non-empty subsegment $a_l, a_{l+1}, \ldots, a_r$ of the array $a$ and a non-negative integer $k$, and assign value $k$ to all elements of the array on the chosen subsegment.

翻译中…

The task is to find out whether $\operatorname{MEX}(a)$ can be increased by exactly one by performing such an operation. In other words, if before the operation $\operatorname{MEX}(a) = m$ held, then after the operation it must hold that $\operatorname{MEX}(a) = m + 1$.

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Recall that $\operatorname{MEX}$ of a set of integers $c_1, c_2, \ldots, c_k$ is defined as the smallest non-negative integer $x$ which does not occur in the set $c$.

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Input

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Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 50\,000$) — the number of test cases. The description of the test cases follows.

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The first line of each test case contains a single integer $n$ ($1 \le n \le 200\,000$) — the number of elements of array $a$.

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The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ($0 \le a_i \le 10^9$) — elements of array $a$.

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It is guaranteed that the sum $n$ over all test cases does not exceed $200\,000$.

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Output

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For each test case, print "Yes" if you can increase $\operatorname{MEX}(a)$ by exactly one by performing the operation from the statement exactly once, otherwise print "No".

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You can output the answer in any case (upper or lower). For example, the strings "yEs", "yes", "Yes", and "YES" will be recognized as positive responses.

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Note

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In the first test case, $\operatorname{MEX}(a) = 0$. If you set all elements of $a$ to $0$, then $\operatorname{MEX}$ of the resulting array will be $1$, and thus will increase by one.

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In the second test case, $\operatorname{MEX}(a) = 1$. If we assign a value of $1$ to the elements of $a$ on a subsegment from $2$ to $3$, we get an array $[0, 1, 1, 0]$ for which $\operatorname{MEX}$ is $2$, and thus is increased by one compared to the original.

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It can be shown that in the third and fourth test cases it is impossible to perform an operation so that the value of $\operatorname{MEX}(a)$ increases by exactly one.

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样例

Input #1
4
3
1 2 1
4
0 2 2 0
4
3 2 0 2
1
0
Output #1
Yes
Yes
No
No
InputCopy OutputCopy
题目信息
题号
1819A
时间限制
1 s
内存限制
256 MB
标签
暴力
贪心

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