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ZOJ Problem Set - 3963
Heap Partition

Time Limit: 2 Seconds      Memory Limit: 65536 KB      Special Judge

A sequence S = {s1, s2, ..., sn} is called heapable if there exists a binary tree T with n nodes such that every node is labelled with exactly one element from the sequence S, and for every non-root node si and its parent sj, sjsi and j < i hold. Each element in sequence S can be used to label a node in tree T only once.

Chiaki has a sequence a1, a2, ..., an, she would like to decompose it into a minimum number of heapable subsequences.

Note that a subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements.

#### Input

There are multiple test cases. The first line of input contains an integer T, indicating the number of test cases. For each test case:

The first line contain an integer n (1 ≤ n ≤ 105) — the length of the sequence.

The second line contains n integers a1, a2, ..., an (1 ≤ ain).

It is guaranteed that the sum of all n does not exceed 2 × 106.

#### Output

For each test case, output an integer m denoting the minimum number of heapable subsequences in the first line. For the next m lines, first output an integer Ci, indicating the length of the subsequence. Then output Ci integers Pi1, Pi2, ..., PiCi in increasing order on the same line, where Pij means the index of the j-th element of the i-th subsequence in the original sequence.

```4
4
1 2 3 4
4
2 4 3 1
4
1 1 1 1
5
3 2 1 4 1
```

```1
4 1 2 3 4
2
3 1 2 3
1 4
1
4 1 2 3 4
3
2 1 4
1 2
2 3 5
```

#### Hint

Author: LIN, Xi
Source: The 14th Zhejiang Provincial Collegiate Programming Contest Sponsored by TuSimple
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