题目描述
You are given an array of numbers $a_1, a_2, \ldots, a_n$. Your task is to block some elements of the array in order to minimize its cost. Suppose you block the elements with indices $1 \leq b_1 < b_2 < \ldots < b_m \leq n$. Then the cost of the array is calculated as the maximum of:
- the sum of the blocked elements, i.e., $a_{b_1} + a_{b_2} + \ldots + a_{b_m}$.
- the maximum sum of the segments into which the array is divided when the blocked elements are removed. That is, the maximum sum of the following ($m + 1$) subarrays: [$1, b_1 − 1$], [$b_1 + 1, b_2 − 1$], [$\ldots$], [$b_{m−1} + 1, b_m - 1$], [$b_m + 1, n$] (the sum of numbers in a subarray of the form [$x,x − 1$] is considered to be $0$).
For example, if $n = 6$, the original array is [$1, 4, 5, 3, 3, 2$], and you block the elements at positions $2$ and $5$, then the cost of the array will be the maximum of the sum of the blocked elements ($4 + 3 = 7$) and the sums of the subarrays ($1$, $5 + 3 = 8$, $2$), which is $\max(7,1,8,2) = 8$.
You need to output the minimum cost of the array after blocking.
Input
The first line of the input contains a single integer $t$ ($1 \leq t \leq 30\,000$) — the number of queries.
Each test case consists of two lines. The first line contains an integer $n$ ($1 \leq n \leq 10^5$) — the length of the array $a$. The second line contains $n$ elements $a_1, a_2, \ldots, a_n$ ($1 \leq a_i \leq 10^9$) — the array $a$.
It is guaranteed that the sum of $n$ over all test cases does not exceed $10^5$.
Output
For each test case, output a single number — the minimum cost of blocking the array.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
The first test case matches with the array from the statement. To obtain a cost of $7$, you need to block the elements at positions $2$ and $4$. In this case, the cost of the array is calculated as the maximum of:
- the sum of the blocked elements, which is $a_2 + a_4 = 7$.
- the maximum sum of the segments into which the array is divided when the blocked elements are removed, i.e., the maximum of $a_1$, $a_3$, $a_5 + a_6 = \max(1,5,5) = 5$.
So the cost is $\max(7,5) = 7$.
In the second test case, you can block the elements at positions $1$ and $4$.
In the third test case, to obtain the answer $11$, you can block the elements at positions $2$ and $5$. There are other ways to get this answer, for example, blocking positions $4$ and $6$.