Codeforces Round 768 (Div. 2)
D
Range and Partition
Codeforces
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原题
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Given an array $a$ of $n$ integers, find a range of values $[x, y]$ ($x \le y$), and split $a$ into exactly $k$ ($1 \le k \le n$) subarrays in such a way that:

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  • Each subarray is formed by several continuous elements of $a$, that is, it is equal to $a_l, a_{l+1}, \ldots, a_r$ for some $l$ and $r$ ($1 \leq l \leq r \leq n$).
  • Each element from $a$ belongs to exactly one subarray.
  • In each subarray the number of elements inside the range $[x, y]$ (inclusive) is strictly greater than the number of elements outside the range. An element with index $i$ is inside the range $[x, y]$ if and only if $x \le a_i \le y$.
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Print any solution that minimizes $y - x$.

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Input

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The input consists of multiple test cases. The first line contains a single integer $t$ ($1 \leq t \leq 3 \cdot 10^4$) — the number of test cases. Description of the test cases follows.

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The first line of each test case contains two integers $n$ and $k$ ($1 \le k \le n \le 2 \cdot 10^5$) — the length of the array $a$ and the number of subarrays required in the partition.

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The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ($1 \le a_i \le n$) where $a_i$ is the $i$-th element of the array.

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It is guaranteed that the sum of $n$ over all test cases does not exceed $2\cdot10^5$.

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Output

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For each test case, print $k+1$ lines.

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In the first line, print $x$ and $y$ — the limits of the found range.

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Then print $k$ lines, the $i$-th should contain $l_i$ and $r_i$ ($1\leq l_i \leq r_i \leq n$) — the limits of the $i$-th subarray.

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You can print the subarrays in any order.

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Note

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In the first test, there should be only one subarray, which must be equal to the whole array. There are $2$ elements inside the range $[1, 2]$ and $0$ elements outside, if the chosen range is $[1, 1]$, there will be $1$ element inside ($a_1$) and $1$ element outside ($a_2$), and the answer will be invalid.

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In the second test, it is possible to choose the range $[2, 2]$, and split the array in subarrays $(1, 3)$ and $(4, 4)$, in subarray $(1, 3)$ there are $2$ elements inside the range ($a_2$ and $a_3$) and $1$ element outside ($a_1$), in subarray $(4, 4)$ there is only $1$ element ($a_4$), and it is inside the range.

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In the third test, it is possible to choose the range $[5, 5]$, and split the array in subarrays $(1, 4)$, $(5, 7)$ and $(8, 11)$, in the subarray $(1, 4)$ there are $3$ elements inside the range and $1$ element outside, in the subarray $(5, 7)$ there are $2$ elements inside and $1$ element outside and in the subarray $(8, 11)$ there are $3$ elements inside and $1$ element outside.

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样例

Input #1
3
2 1
1 2
4 2
1 2 2 2
11 3
5 5 5 1 5 5 1 5 5 5 1
Output #1
1 2
1 2
2 2
1 3
4 4
5 5
1 1
2 2
3 11
InputCopy OutputCopy
题目信息
题号
1631D
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。