Ashish has a binary string $s$ of length $n$ that he wants to sort in non-decreasing order.
He can perform the following operation:
- Choose a subsequence of any length such that its elements are in non-increasing order. Formally, choose any
$k$such that$1 \leq k \leq n$and any sequence of$k$indices$1 \le i_1 \lt i_2 \lt \ldots \lt i_k \le n$such that$s_{i_1} \ge s_{i_2} \ge \ldots \ge s_{i_k}$. - Reverse this subsequence in-place. Formally, swap
$s_{i_1}$with$s_{i_k}$, swap$s_{i_2}$with$s_{i_{k-1}}$,$\ldots$and swap$s_{i_{\lfloor k/2 \rfloor}}$with$s_{i_{\lceil k/2 \rceil + 1}}$(Here$\lfloor x \rfloor$denotes the largest integer not exceeding$x$, and$\lceil x \rceil$denotes the smallest integer not less than$x$)
Find the minimum number of operations required to sort the string in non-decreasing order. It can be proven that it is always possible to sort the given binary string in at most $n$ operations.
Input
The first line contains a single integer $t$ $(1 \le t \le 1000)$ — the number of test cases. The description of the test cases follows.
The first line of each test case contains an integer $n$ $(1 \le n \le 1000)$ — the length of the binary string $s$.
The second line of each test case contains a binary string $s$ of length $n$ containing only $0$s and $1$s.
It is guaranteed that the sum of $n$ over all test cases does not exceed $1000$.
Output
For each test case output the following:
- The minimum number of operations
$m$in the first line ($0 \le m \le n$). - Each of the following
$m$lines should be of the form:$k$$i_1$$i_2$...$i_{k}$, where$k$is the length and$i_1 \lt i_2 \lt ... \lt i_{k}$are the indices of the chosen subsequence. For them the conditions from the statement must hold.
Note
In the first test case, the binary string is already sorted in non-decreasing order.
In the second test case, we can perform the following operation:
$k = 4:$choose the indices$\{1, 3, 4, 5\}$$\underline{1}$$0$$\underline{1}$$\underline{0}$$\underline{0}$$\rightarrow $$\underline{0}$$0$$\underline{0}$$\underline{1}$$\underline{1}$
In the third test case, we can perform the following operation:
$k = 3:$choose the indices$\{3, 5, 6\}$$0$$0$$\underline{1}$$0$$\underline{0}$$\underline{0}$$\rightarrow $$0$$0$$\underline{0}$$0$$\underline{0}$$\underline{1}$
样例
3
7
0011111
5
10100
6
001000
0
1
4 1 3 4 5
1
3 3 5 6
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