#E. Fill the Matrix

    Type: RemoteJudge 2000ms 256MiB

Fill the Matrix

You cannot submit for this problem because the contest is ended. You can click "Open in Problem Set" to view this problem in normal mode.

Description

There is a square matrix, consisting of nn rows and nn columns of cells, both numbered from 11 to nn. The cells are colored white or black. Cells from 11 to aia_i are black, and cells from ai+1a_i+1 to nn are white, in the ii-th column.

You want to place mm integers in the matrix, from 11 to mm. There are two rules:

  • each cell should contain at most one integer;
  • black cells should not contain integers.

The beauty of the matrix is the number of such jj that j+1j+1 is written in the same row, in the next column as jj (in the neighbouring cell to the right).

What's the maximum possible beauty of the matrix?

The first line contains a single integer tt (1t1041 \le t \le 10^4) — the number of testcases.

The first line of each testcase contains a single integer nn (1n21051 \le n \le 2 \cdot 10^5) — the size of the matrix.

The second line contains nn integers a1,a2,,ana_1, a_2, \dots, a_n (0ain0 \le a_i \le n) — the number of black cells in each column.

The third line contains a single integer mm (0mi=1nnai0 \le m \le \sum \limits_{i=1}^n n - a_i) — the number of integers you have to write in the matrix. Note that this number might not fit into a 32-bit integer data type.

The sum of nn over all testcases doesn't exceed 21052 \cdot 10^5.

For each testcase, print a single integer — the maximum beauty of the matrix after you write all mm integers in it. Note that there are no more integers than the white cells, so the answer always exists.

Input

The first line contains a single integer tt (1t1041 \le t \le 10^4) — the number of testcases.

The first line of each testcase contains a single integer nn (1n21051 \le n \le 2 \cdot 10^5) — the size of the matrix.

The second line contains nn integers a1,a2,,ana_1, a_2, \dots, a_n (0ain0 \le a_i \le n) — the number of black cells in each column.

The third line contains a single integer mm (0mi=1nnai0 \le m \le \sum \limits_{i=1}^n n - a_i) — the number of integers you have to write in the matrix. Note that this number might not fit into a 32-bit integer data type.

The sum of nn over all testcases doesn't exceed 21052 \cdot 10^5.

Output

For each testcase, print a single integer — the maximum beauty of the matrix after you write all mm integers in it. Note that there are no more integers than the white cells, so the answer always exists.

Sample Input 1

6
3
0 0 0
9
4
2 0 3 1
5
4
2 0 3 1
6
4
2 0 3 1
10
10
0 2 2 1 5 10 3 4 1 1
20
1
1
0

Sample Output 1

6
3
4
4
16
0

比赛1

Not Attended
Status
Done
Rule
IOI
Problem
6
Start at
2023-6-14 10:45
End at
2023-6-14 12:45
Duration
2 hour(s)
Host
Partic.
8