Java: Largest rectangle in histogram

Difficulty Level: HARD

Problem Statement:

You are given an array of integers A[], where each element A[i] represents the height of a bar in a histogram. The width of each bar is 1. The task is to return the area of the largest histogram.

Input:

N =6, heights[] = {5,6,4,3,7,5}

Output:

The maximum area is 18