Grokking 75: Top Coding Interview Questions

0% completed

​

Introduction to Monotonic Stack

Definition of Monotonic Stack

A Monotonic Stack is a special kind of stack, which maintains its elements in a specific order. Unlike a traditional stack, where elements are placed on top of one another based on when they arrive, a Monotonic Stack ensures that the elements inside the stack remain in an increasing or decreasing order. This is achieved by enforcing specific push and pop rules, depending on whether we want an increasing or decreasing monotonic stack.

Relevance in Coding Interviews

Monotonic Stacks are powerful tools in coding interviews due to their unique capabilities

.....

.....

.....

Like the course? Get enrolled and start learning!
K

karrad

· 3 years ago

  • Input: nums1 = [9,7,1], nums2 = [1,7,9,5,4,3]
  • Output: [-1,9,7]

In this example, we first take 9 and compare to every number to right of 9 in nums2. No number >9 so -1

Then 7. The 1st number to right of 7 (i.e only consider last 4 numbers in nums2) is 9

Now we consider 1. If we go by the same logic, we should only consider 5,4,3 in nums2. Why is the answer 7? Should it not be 5?

Thanks

M

Show 2 replies
Kinshuk Agrawal

Kinshuk Agrawal

· 2 years ago

It would be nice to have such a comprehensive explanation + pseudo code for every pattern

A

Anand Mohan

· 3 years ago

There seems to be a mistake in the image. We are using monotonically decreasing stack.