Disjoint Union Sets

It is a rainy Sunday morning in the Twin Cities of Minneapolis and St. Paul. Rain started last evening around 08:00 PM and according to the weather forecast will subside later tonight around 10:00 PM. Not a nice day to be outdoors or grilling.

Last Friday my son mentioned that he would be going shopping on Saturday morning to the Costco Minneapolis Business Center Warehouse. My wife and I decided to join him at 07:00 AM (opening time). We met in the parking lot, donned our gloves and mask, and headed in. We have been at the Restaurant Depot many times, but were nicely surprised with the size of the Costco facility and the variety of items. From now on my wife and I will make the trip from home (30 minutes about 20 miles away) a couple times a month to the Costco in Minneapolis. We believe it is worth the drive.

My wife and I cook and bake. I like to bake deserts, breads and Italian cuisine. My wife cooks lunch during the workdays. We both cook on weekends. We have breakfast which I prepare every day and we both skip dinner. The point that I am trying to make is that we did not start cooking or baking due to the coronavirus pandemic.

Last week we noticed that we were running very low on yeast. We went grocery shopping last Tuesday morning and where not able to find yeast at Costco in Eagan, MN or Trader Joe’s in St. Paul. Back home, I went to Amazon.com and ordered a 2 pound pouch of Red Star dry yeast. The total after taxes (we do have Amazon Prime) came to $24.99 USD. I thought it was expensive but it seems that every one and their brother are baking now a day. The delivery will be sometime tomorrow (Monday).

While at Costco we found lots of Red Star dry yeast in the same 2 lb pouches we ordered from Amazon. That is the same yeast we have been using for over a decade. What we found disgusting was that Costco had the same 2 lb pouches of yeast for under $4.50 USD each. We bought two pouches (totaling 4 lbs) for about $9.00 USD. They should last a year or so. Continue reading “Disjoint Union Sets”

First Duplicate

This morning in the Twin Cities of Minneapolis and St. Paul we woke up with a temperature of -11 F. The central heating unit worked overtime last night. It was quite dry indoors. Not sure why this happens due to the fact that the central heating as a built in humidifier and air exchange sub systems.

Yesterday morning I read the article “Do You Solve Programming Problems or Complete Exercises? (The Difference Matters.)” by Amy Haddad. She makes a difference between problem-solving and solving exercises. I agree with her interpretation. If interested read her article and possibly comment in her or my post.

Yesterday evening, I was browsing YouTube and ran into the video “Google Coding Interview Question – firstDuplicate” by Nicholas White. Continue reading “First Duplicate”

Design a System like Yelp

Last week I was talking with a software manager about the design of a feature for Yelp. For starters I am not a Yelp user. If you are like me, you can find more about Yelp in this Wikipedia link.

It seems that Yelp is a business directory and uses a crowd-source review forum to collect information and ratings about different businesses (i.e., barber shops, cinemas, coffee shops, restaurants). It happens that I use OpenTable for restaurant-reservations. Apparently on both platforms one can get nearby restaurants of desired types in a specified distance so you can decide where to go for dinner (or for that matter for any meal at any time) tonight. A side fact, both companies happen to be headquartered in the San Francisco, California area. Continue reading “Design a System like Yelp”

A* Search Algorithm

As I mentioned in my last post, I read the article “A* search: what’s in a name?” by James W. Davis and Jeff Hachtel. If interested, you may find the article in Communications of the ACM, December 2019, Vol. 63 No. 1, Pages 36-37. The article deals with the name of a search algorithm that was originally published in 1968 by Peter Hart, Nils Nilsson and Bertram Raphael of Stanford Research Institute.

My interest was not much about the name but to be able to experiment and understand the algorithm. There are so many algorithms in Computer Science that adding one more to my list is always welcomed. I do not plan on memorizing the algorithm but if the time comes when I might need to search a graph, I will have one more choice in my toolkit. Continue reading “A* Search Algorithm”

Organizing Containers of Balls

Hope you had a happy Thanksgiving Day with your family. As usual there is lots of anticipation and suddenly it is over.

Some years my wife and I have gone out shopping on Black Friday, but as time goes by, it seems that most of the shopping can be done on-line. For that, the best day seems to be Cyber Monday. Besides the ability of shopping from the computer on Cyber Monday, there was a lot of snow and ice over in the Twin Cities of Minneapolis and St. Paul over the Thanksgiving holiday. One of my wife’s nephews posted on Facebook a video of cars slipping and sliding all over in Minneapolis. Continue reading “Organizing Containers of Balls”

Cats and a Mouse

In the past few weeks I have been reading several articles about how great Visual Studio Code is and how software developers are starting to use as their main IDE. I have been using VS Code on and off but have made up my mind that from now on for Java development I will only use Visual Studio Code. I have installed Eclipse and IntelliJ in my machine, both of which I have used for Java development. I will leave both of them installed for compatibility purpose only. Will let you know my findings towards the end of the year. Continue reading “Cats and a Mouse”

Majority Element

Last weekend my wife and I stopped to visit our son who also lives in the Twin Cities of Minneapolis and St. Paul. On our last trip to Europe, our granddaughters asked us if we could get for their dad a bottle of flavored vodka in the duty free store in the Schiphol airport in Amsterdam. At the time looked like a good idea. He seems to enjoy vodka. When we returned home the girls gave their dad the bottle. Continue reading “Majority Element”

Find Damaged

Last week I had the opportunity to chat with a principal researcher / architect who works for one of the top 10 in the list of the World’s Most Admired Companies.

He was explaining to me how to do a search in a very long string. In this set of two or three blogs I will try to determine how to perform a search of damaged patterns. Continue reading “Find Damaged”

Java Priority Queue

Yesterday was sunny and all the snow on our deck has melted away, so my wife and I decided to grill for the first time this season. I believe the temperature went up to 58 F. The day was not as warm as I would have liked, but on occasions I went out just wearing a t-shirt. We grilled homemade hamburgers, potatoes, and corn. We fixed on the stovetop mushrooms with onions and garlic. All was very good and as usual we made too much food. That is fine because we will just warm up leftover today. Continue reading “Java Priority Queue”

RabbitMQ – Hello World

Good morning. In this post we will explore RabbitMQ by Pivotal. RabbitMQ is a message broker. Message brokers are considered middleware. Applications subscribe to a queue to send and receive messages. Another queue broker I have used in products is MSMQ from Microsoft. In this post we will only experiment with RabbitMQ. You may decide to use message queues to communicate between microservices. Continue reading “RabbitMQ – Hello World”