#include <bits/stdc++.h>
using namespace std;

int main() 
{
    vector<int> a{6,2,5,4,5,1,6};
    stack<int> s;
    int area=0;
    int maxArea=0;
    s.push(0);
    int i=1;
    while(i<a.size()) {
      if(a[i]>a[s.top()]) {
        s.push(i);
      }
      else {
        while(!s.empty() && a[i]<a[s.top()]) {
          if(s.size()==1) {
            area=a[s.top()]*i;
            s.pop();
          }
          else {
            int height=a[s.top()];
            s.pop();
            int width=i-s.top()-1;
            area=height*width;
          }
          cout<<area<<" ";
          maxArea=max(maxArea,area);
        }
        s.push(i);
      }
      i++;
    }
    while(!s.empty()) {
          if(s.size()==1) {
            area=a[s.top()]*i;
            s.pop();
          }
          else {
            int height=a[s.top()];
            s.pop();
            int width=i-s.top()-1;
            area=height*width;
          }
          cout<<area<<" ";
          maxArea=max(maxArea,area);
    }
    cout<<endl<<"Max Area Region Under Histogram -> "<<maxArea;
      
    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
}