Fun with Even Subarrays

1000ms

262144K

Description:

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

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 $$$a_{l+i}$$$.

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

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

Input:

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.

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

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 $$$a$$$.

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

Output:

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.

Sample Input:

Sample Output:

Note:

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

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.

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

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 $$$[3, 3, 3, 3]$$$.

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

Informação

Provedor Codeforces

Código CF1631B