#include<iostream>
#include<vector>
#include<algorithm>
#include<stack>

using namespace std;

 bool compare(const vector<int>&v1, const vector<int>&v2){
   return v1[0]<v2[0];
 }

void mergeOverlappingIntervals(vector<vector<int>>& arr){
   stack<pair<int,int>> merge;
   sort(arr.begin(), arr.end(),compare);
   merge.push({arr[0][0],arr[0][1]});
   for(int i = 1;i<arr.size();i++){
       pair<int,int>&p = merge.top();
       if(p.second>arr[i][0]){
           p.first = min(arr[i][0],p.first);
           p.second = max(arr[i][1],p.second);
       }
       else{
           merge.push({arr[i][0],arr[i][1]});
       }
   }

   string ans = "";
   while(!merge.empty()){
       ans = to_string(merge.top().first) +" "+ to_string(merge.top().second) + "\n"+ans;
       merge.pop();
       
   }
   cout<<ans<<endl;
   
}


int main(){
    int n;
    cin >> n ;
   
    vector<vector<int>> arr( n , vector<int>(2) );
   
   
   
    // input
    for(int i = 0; i < n ; i++ ){
        cin >> arr[i][0];
        cin >> arr[i][1];
    }
   
   
    mergeOverlappingIntervals(arr);
   
}

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
}