This is the coding challenge of Fetch Rewards.
Author: Xin Jiang
Email: xin@jiangx.in
Link to My Resume
Write a web service that takes in a string and returns a boolean to indicate whether or not a word is a pyramid word. A word is pyramid word if you can arrange the letters in increasing frequency, starting with 1 and counting without gaps and without duplicates.
This project is using Kotlin and Spring Boot. It has a Application class and one controller called isPyramid, which is a GET method.
This is a maven project and runs on port 10010.
This project assumes you input a valid, not null string with only letters. i.e., a valid "word".
The controller will first compute the frequency for each word using HashMap. This takes O(N) of time.
Then the sorting will take constant time since there is a maximum of 26 keys in the HashMap.
Then it iterates through the sorted map to determine whether it is a pyramid word. This also takes constant time.
So the overall time complexity is O(N).
Clone the repository:
git clone https://github.com/XinJiangCN/Fetch-Rewards
Install the dependencies:
mvn clean install
Maven should be installed
Start the App:
mvn spring-boot:run
Note: port 10010 must be available
Open a web browser and test:
http://localhost:10010/isPyramid?str=TARGET,
where TARGET is the string you may want to test.
The web page will simply display whether the given string is a pyramid word.