LeetCode 160 Intersection of Two Linked Lists in Java

In this post I will be solving LeetCode 160 Intersection of Two Linked Lists using the Java programming language.

Given the heads of two singly linked-lists headA and headB, 
return the node at which the two lists intersect. 
If the two linked lists have no intersection at all, return null.

Custom Judge:

The inputs to the judge are given as follows (your program is not given these inputs):

o intersectVal - The value of the node where the intersection occurs.
  This is 0 if there is no intersected node.
o listA - The first linked list.
o listB - The second linked list.
o skipA - The number of nodes to skip ahead in listA (starting from the head) 
  to get to the intersected node.
o skipB - The number of nodes to skip ahead in listB (starting from the head) 
  to get to the intersected node.

The judge will then create the linked structure based on these inputs and pass the two heads, 
headA and headB to your program.
If you correctly return the intersected node,
then your solution will be accepted.

Constraints:

o The number of nodes of listA is in the m.
o The number of nodes of listB is in the n.
o 1 <= m, n <= 3 * 104
o 1 <= Node.val <= 105
o 0 <= skipA < m
o 0 <= skipB < n
o intersectVal is 0 if listA and listB do not intersect.
o intersectVal == listA[skipA] == listB[skipB] if listA and listB intersect.

Related Topics:

* Hash Table
o Linked List
* Two Pointers

Follow up:

* Could you write a solution that runs in O(m + n) time and use only O(1) memory?

If interested I suggest you get the current description from LeetCode before you start coding. Continue reading “LeetCode 160 Intersection of Two Linked Lists in Java”

Intersection of Two Arrays

Good day fellow software developers and engineers! It is a gloomy day in the Twin Cities of Minneapolis and St. Paul. Hopefully the weather is nicer in your neck of the woods.

Today I picked up the LeetCode 349 Intersection of Two Arrays problem. To be honest with you I do not recall why I did it. Due to thunderstorms I had to power down my computers a couple times today. I just lost track of the reason why I picked this problem. Continue reading “Intersection of Two Arrays”

Red John is back

It is another warm Tuesday morning in the Twin Cities of Minneapolis and St. Paul. When the COVID-19 pandemic started my wife and I stopped walking on a daily schedule. A couple weeks ago we started walking. Slowly we are trying to get to 10,000 steps a day. Currently we are around 6,500 steps. In addition after every 2-hour block of work I get on a stationary bike and pedal fast and furious for 5 minutes. I tend to get 4 to 5 short sessions per day. My wife decided to skip the bike. That said; we both are starting to feel the benefits of exercising once again. We love it!

On a separate note my best friend sent me a message that he was starting to test ProtonMail for personal and potentially commercial use. I replied that I have been experimenting with it on my defunct Pixel 4 cell phone. After it died with less than two years of use a couple weeks ago, I switched for the first time to an iPhone. I am still installing applications. Today I will install ProtonMail and will continue testing the service. About three months ago I mentioned ProtonMail on my post Largest Triple Products – Revisited. I like the encryption and the fact that they do not use or sell your personal information. Continue reading “Red John is back”