Largest Rectangle In Histogram - Hackerrank

//dpw4112001
// Coding Interview Question
/*

    Resourse : Youtube Video By Coding Blocks
    Other Approaches:
    Brute Force : O(N^2)
    Divide and Conquer : O(NlogN)
    Stacks : O(N)

*/
#include<bits/stdc++.h> 
using namespace std; 
int getMaxArea(int hist[], int n) 
{      stack<int> s; 

    int max_area = 0;  
    int tp; // To store top of stack 
    int area_with_top; 
    int i = 0; 
    while (i < n) 
    { 
        // If this bar is higher than the bar on top 
        // stack, push it to stack 
        if (s.empty() || hist[s.top()] <= hist[i]) 
            s.push(i++); 
        else
        { 
            tp = s.top(); // store the top index 
            s.pop(); // pop the top 
            area_with_top = hist[tp] * (s.empty() ? i : 
                                i - s.top() - 1); 
            //Finding Maximum Area
            if (max_area < area_with_top) 
                max_area = area_with_top; 
        } 
    } 


    // Calculating area for remaing non-popped bars
    while (s.empty() == false) 
    { 
        tp = s.top(); 
        s.pop(); 
        area_with_top = hist[tp] * (s.empty() ? i : 
                                i - s.top() - 1); 
        if (max_area < area_with_top) 
            max_area = area_with_top; 
    } 

    return max_area; 
} 

int main() 
{ 
    int n;
    cin >> n;
    int hist[n];
    for(int i=0;i<n;i++)
    cin >> hist[i];
    cout << getMaxArea(hist, n); 
    return 0; 
}