#include <cstdint>
#include <iostream>
#include <set>
#include <vector>

using namespace std;

void solve() {
    int N; cin >> N;
    
    vector<int> A(N);
    for (int &x : A) cin >> x, --x;
    
    vector<int> cnt(N, 0), is_last(N, 0), last_pos(N, -1);
    for (int i = N-1; i >= 0; --i) {
        if (!cnt[A[i]]++) is_last[i] = 1, last_pos[A[i]] = i;
    }
    
    vector<int> ans;
    multiset<int> st;
    int l = 0, r = -1, flag = 0;
    while (r+1 < N) {
        while (r+1 < N and (r == -1 or !is_last[r])) {
            ++r;
            if (is_last[last_pos[A[r]]]) st.emplace(A[r]);
        }
         cout<<"*";
            for(auto &i:st)cout<<i<<" ";
            cout<<"&";
        if (st.size()) {
            ans.emplace_back(flag ? *begin(st) : *rbegin(st)), flag ^= 1;
            is_last[last_pos[ans.back()]] = 0;
            while (A[l] != ans.back()) {
                if (auto it = st.find(A[l++]); it != end(st)) st.erase(it);
            }
            st.erase(A[l++]); // no find
            cout<<'\n';
             cout<<"#";
            for(auto &i:st)cout<<i<<" ";
            cout<<"^";
           
        }
    }
    
    int M = ans.size();
    cout << M << '\n';
    for (int i = 0; i < M; ++i) cout << ans[i] + 1 << " \n"[i == M-1];
}

int32_t main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    
    int t = 1; cin >> t;
    for (int _ = 1; _ <= t; ++_)
        solve();
    
    return 0;
}

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}