084. Largest Rectangle in Histogram

Given *n *non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest
rectangle in the histogram.
Below is a histogram where width of each bar is 1, given height =[2,1,5,6,2,3].

The largest rectangle is shown in the shaded area, which has area =10unit.
For example,
Given heights =[2,1,5,6,2,3],
return10.

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My solution used the monotone stack with time complexity O(N).

class Solution {
public:
    int largestRectangleArea(vector& heights) {
      if(heights.size() == 0) return 0;
      heights.push_back(0);
      stack myStack;
      int maxArea = 0;
      for(int i = 0; i < heights.size(); i++){
        if(myStack.empty() || heights[i] > heights[myStack.top()]){
          myStack.push(i);
        }else{
          int top = heights[myStack.top()];
          myStack.pop();
          int width = i - (myStack.empty() ? -1 : myStack.top()) - 1;
          maxArea = max(maxArea, top*width);
          i--;
        }
      }
      return maxArea;
    }
};