## Is Permutation

Let’s define the requirements for this algorithm. We are given two sets of integers. The idea is to check if the sets are permutations of each other. If they are, return YES; otherwise return NO.

First let’s make sure we agree with the definition of permutation. For the sets to be permutations we must have the same number of elements in both sets. Each set must have the same counts for each entry. For example if the sets are:

1 2 3 4 5 6

6 5 4 3 2 1

Then we would return YES. Both sets have the same length (six in this case) the numbers are the same on both sets, and the count of each number matches (one in this case).

7 6 5 0 9 7

7 6 1 0 9 7

Given that 5 is in the first set, but not in the second and 1 is in the second, but not in the first, these are not permutations of each other so we would return NO. Continue reading “Is Permutation”

## 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”

## More than a List of Words

When indexing text based word frequency / relevance which may be applicable for web searches, one of the procedures used is to create a term frequency (tf) array followed by an inverse document frequency (idf) one. You can read more about this here.

In a previous post I experimented with some text in order to build hashmaps with the words of sentences (to keep things in perspective for a blog post). In that post I used a string that I copied from a course I took some years ago. The sting was already preprocessed. The text had already been stripped off punctuation marks. Continue reading “More than a List of Words”

## Word Pattern

It seems to me that LeetCode (https://leetcode.com/) has more complex challenges than HackerRank (https://www.hackerrank.com/domains?h_r=logo). Their approach to testing the solutions is different. They not only test for correctness but they also check for execution time.

In the next few weeks will concentrate in solving challenges from LeetCode. I will also try to get to weekend competitions if they are relatively early in the day (I am a morning person).

If interested take a look at the requirements for this challenge using the following link:  https://leetcode.com/problems/word-pattern/ Continue reading “Word Pattern”