InterviewBit Problems   Max Rectangle in Binary Matrix : Solved

About the Max Rectangle in Binary Matrix : Solved category (1)
Using histogram area O(N^2) in Swift (1)
Easy stack based approach (1)
Simple and Clean C++ solution (1)
Easiest to understand O(n2) c++ solution (1)
[C++] long but easy to understand. With description (1)
A bit Long but Easy To Digest Sol-JAVA (1)
Short and sweet solution using c++ without dp (1)
Stack Shortest Solution C++ O(nm) (1)
Using Max Sum Rectangle concept (1)
Simple Solution Using Maximum Histogram Area (1)
C++ Solution in O(N*M) time (1)
O(N^2) solution (1)
How to do it in less than O(n^2) (2)
Hey did i get bonus? my code complexity was O(n^2) . If Yes then Where is it? o (1)