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

int main() {
    // Write your code here
   string names;
   getline(cin,names);
    unordered_map<string ,int> nameCount;
    string str;
    for(int i = 0;i<names.size();i++){
        if(names[i] == ' '|| i == names.size() -1 ){
          // cout<<1<<" ";
          //cout<<str<<endl;
            nameCount[str]++;
           // cout<<nameCount[str]<<endl;
            str.erase(0);
        }
        
        else{
        str.push_back(names[i]);
        }
        // cout<<str<<endl;
        // cout<<str<<endl;
    }
      unordered_map<string ,int>::iterator it;
    str.erase(0);
    // for(int i = 0;i<names.size();i++){
    //     if(names[i] == ' '){
    //       cout<<str<<endl;
    //         if(nameCount[str]>=2){
    //           // cout<<2<<" ";
    //             cout<<str<<" "<<nameCount[str]<<endl;
    //             str.erase(0);
    //         }
    //     }
    //     else{
    //     str.push_back(names[i]);
        
    //     }
    int count = 0;   
    for(auto i:nameCount){
      if(i.second ==2 ){
      cout<<i.first<<" "<<i.second<<endl;
      count++;
        
      }
      
    }
    if(count == 0){
      cout<<-1<<endl;
    }
   
}
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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
}