Mock interview experience III

Oct. 16, 2018

Introduction

I learn from my own mock interview experience. After the mock interview on Oct. 15, 2018, I got the complaint from the interviewee. So I decided to spend extra 30 minutes to help and have discussion with the interviewee.

I had chance to work with the interviewee this time, and then we had good discussion how to solve those algorithms.

How to explain the approach? 

Here are the hints I gave in the mock interview. The algorithm is called longest univalue path on Leetcode.com, easy level tree algorithm.

	Leetcode: longest univalue path
	hint:
	instead of working on longest path directly, kind of greedy, break into two parts.
	length1 = one is the root to leaf node longest path -> left side
	length2 = one is the root to leaf node longest path -> right side
	path cross the root = length1 + length2
	In order to calculate length1 or length2, recursive can be used to calculate. Brute force all paths
	from the tree, any node to any node, n nodes in the tree, n * (n-1) = O(n*n). It is hard to compute.
	Instead brute force every node as root node of the tree, determine the longest path cross the root node.
	More hint:
	work on those simple trees:
	4 4 4 4
	/ / \ / \
	4 4 4 4 4
	/
	4
	Recursive function:
	return 0, 1, 1, 2
	longest path:
	return 0, 1, 2, 3

view raw longest univalue path - hints to help hosted with ❤ by GitHub

My advice

I also wrote down my advice after the mock interview as the interviewer.