LeetCode 141 Linked List Cycle in Java

In this post we will solve the LeetCode 141 Linked List Cycle problem.

Given head, the head of a linked list, 
determine if the linked list has a cycle in it.

There is a cycle in a linked list 
if there is some node in the list that can be reached again by continuously following the next pointer. 

Internally, pos is used to denote the index of the node that tail's next pointer is connected to. 
Note that pos is not passed as a parameter.

Return true if there is a cycle in the linked list. 
Otherwise, return false.


o The number of the nodes in the list is in the range [0, 10^4].
o -10^5 <= Node.val <= 10^5
o pos is -1 or a valid index in the linked-list.

Related Topics:

o Hash Table
o Linked List
o Two Pointers

We are given a singly linked list and are asked to determine if there is a cycle in it. If interested in the problem please take a look at the current description of it in the LeetCode website. Continue reading “LeetCode 141 Linked List Cycle in Java”

LeetCode 575. Distribute Candies in Java

In this post we will solve the LeetCode 575. Distribute Candies problem.

This problem is not too difficult to get to an answer. Not sure if it was network traffic, but the different attempts, which were accepted, required a different approach. Once you get a first pass accepted, I would suggest that before you leave the LeetCode website, take a look at the implementations that perform best. I was going to implement some of those approaches but got late and had to move on with other tasks.

Alice has n candies, where the ith candy is of type candyType[i]. 
Alice noticed that she started to gain weight, so she visited a doctor.

The doctor advised Alice to only eat n / 2 of the candies she has (n is always even). 
Alice likes her candies very much, 
and she wants to eat the maximum number of different types of candies while still following the doctor's advice.

Given the integer array candyType of length n, 
return the maximum number of different types of candies she can eat if she only eats n / 2 of them.


o n == candyType.length
o 2 <= n <= 10^4
o n is even.
o -10^5 <= candyType[i] <= 10^5

In this problem Alice is given different candies. As we will see in the examples, a type of candy may appear once or more times. Continue reading “LeetCode 575. Distribute Candies in Java”

Contains Duplicate

Good day! It is Thursday morning and it is a typical gloomy and cold winter day in the Twin Cities of Minneapolis and St. Paul. The good thing is that is Thursday. One more day to go to and we can start enjoying the weekend. For most of us the weekend will be 2-days long. It is different from the past two weekends in which most people enjoyed 3 or 4 days off work.

Due to COVID-19 my wife and I just leave home for grocery shopping and healthcare appoints when needed. The good thing is that vaccination has started in the USA and hopefully in a few more months most of us will be vaccinated and can start getting back to normal. We all will see what happens. Continue reading “Contains Duplicate”

13 to 15 Java Questions

I have noticed that multiple times in a week I wake up and check my phone for the time and it is 04:47 AM. Given that I live in the Twin Cities of Minneapolis and St. Paul, there is some day light at that time. I recall a few years ago when I would get up around 05:00 AM to walk the dogs.

I do have an alarm set for 05:00 AM 7 days a week. In addition I have set an appointment in my Google calendar for the same time. Today after waking up at 04:47 AM I checked the calendar to see if there was a message or notification set for 15 minutes before (04:45 AM). Both notification and email are set for 05:00 AM. Continue reading “13 to 15 Java Questions”