Codeforces Round 768 (Div. 2)
B
Fun with Even Subarrays
Codeforces
1100
原题
← AC →
翻译中…

You are given an array $a$ of $n$ elements. You can apply the following operation to it any number of times:

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  • Select some subarray from $a$ of even size $2k$ that begins at position $l$ ($1\le l \le l+2\cdot{k}-1\le n$, $k \ge 1$) and for each $i$ between $0$ and $k-1$ (inclusive), assign the value $a_{l+k+i}$ to $a_{l+i}$.
翻译中…

For example, if $a = [2, 1, 3, 4, 5, 3]$, then choose $l = 1$ and $k = 2$, applying this operation the array will become $a = [3, 4, 3, 4, 5, 3]$.

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Find the minimum number of operations (possibly zero) needed to make all the elements of the array equal.

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Input

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The input consists of multiple test cases. The first line contains a single integer $t$ ($1 \leq t \leq 2 \cdot 10^4$) — the number of test cases. Description of the test cases follows.

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The first line of each test case contains an integer $n$ ($1 \leq n \leq 2 \cdot 10^5$) — the length of the array.

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The second line of each test case consists of $n$ integers $a_1, a_2, \dots, a_n$ ($1 \leq a_i \leq n$) — the elements of 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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Print $t$ lines, each line containing the answer to the corresponding test case — the minimum number of operations needed to make equal all the elements of the array with the given operation.

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Note

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In the first test, all elements are equal, therefore no operations are needed.

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In the second test, you can apply one operation with $k=1$ and $l=1$, set $a_1 := a_2$, and the array becomes $[1, 1]$ with $1$ operation.

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In the third test, you can apply one operation with $k=1$ and $l=4$, set $a_4 := a_5$, and the array becomes $[4, 4, 4, 4, 4]$.

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In the fourth test, you can apply one operation with $k=1$ and $l=3$, set $a_3 := a_4$, and the array becomes $[4, 2, 3, 3]$, then you can apply another operation with $k=2$ and $l=1$, set $a_1 := a_3$, $a_2 := a_4$, and the array becomes $[3, 3, 3, 3]$.

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In the fifth test, there is only one element, therefore no operations are needed.

翻译中…

样例

Input #1
5
3
1 1 1
2
2 1
5
4 4 4 2 4
4
4 2 1 3
1
1
Output #1
0
1
1
2
0
InputCopy OutputCopy
题目信息
题号
1631B
时间限制
1 s
内存限制
256 MB
标签
动态规划
贪心

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