#include <bits/stdc++.h>
#define int long long int
#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define PI 3.141592653589793238462
#define set_bits __builtin_popcountll
#define INF 1e18
using namespace std;
using namespace std::chrono;

void google(int t) {cout << "Case #" << t << ": ";}
int gcd(int a, int b) { return b ? gcd(b, a%b) : a; }
string strrev(string s){
  reverse(s.begin(),s.end());
  return s;
}

const int m=1e7;
vector<int> sieve(){
  vector<bool> a(m+1,true);
  vector<int> v;
  a[0]=false;
  a[1]=false;
  for(int p=2;p*p<=m;p++){
    if(a[p])
    for(int i=p*p;i<=m;i+=p){
      if(a[i])
      a[i]=false;
    }
  }
  for(int i=2;i<=m;i++){
        if(a[i])
        v.push_back(i);
    }
  return v;
}
int fp(int a,int b){
  int res=1;
  while(b){
    if(b&1){
      res=res*a;
      b--;
    }
    //now b is even
    a=a*a;
    b=b>>1;
  }
  return res;
}

bool mycomp(pair<char,int> p1,pair<char,int> p2){
  return p1.second>p2.second;
}

int32_t main()
{
    auto start1 = high_resolution_clock::now();
    fastio();
    int t;
    cin>>t;
    int tc=t;
    while(t--){
        google(tc-t);
        string s;
        cin>>s;
        string temp=s;
        int l=s.length();
        unordered_map<char,int> mp;
        for(auto x:s)
        mp[x]++;
        int flag=0;
        for(auto x:mp){
          if(x.second>l/2){
            flag=1;
            break;
          }
        }
        if(flag){
          cout<<"IMPOSSIBLE\n";
          continue;
        }
        vector<pair<char,int>> v;
        
        int j=0;
        for(auto &x:mp)
        v.push_back({x.first,x.second});
        
        sort(v.begin(),v.end(),mycomp);
        
        for(int i=0;i<l;i++){
          for(int j=0;j<v.size();j++){
            if(temp[i]!=v[j].first && v[j].second>0){
              s[i]=v[j].first;
              v[j].second--;
              break;
            }
          }
        }
        
        for(int i=0;i<l;i++)
        if(s[i]==temp[i])
        swap(s[i],s[i-1]);
        
        cout<<s<<"\n";
    }
   auto stop1 = high_resolution_clock::now();
   auto duration = duration_cast<microseconds>(stop1 - start1);
  
    int tm=(double)duration.count()/1000;
    //cout << "Time: " << tm << " ms" << endl;
   return 0;
}
by

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
}