Purely Functional Solutions of LeetCode Problems

I wonder if there exist some methods to solve the algorithm problems of LeetCode in a purely functional way. As a result, I created this project. I use a lot of purely functional data structures described in Chris Okasaki's Purely Functional Data Structures. If someone wants to see the detailed implementation, please refer to the libs directory.

To see how to use the libs, please check the test parts in each file.

Each solution file contains some tests, which is not a part of the solution itself.

Many Problems need to memorize the computation results. Sometimes I use mutable hash tables to memorize the results. In the next stage, I will try to use a purely functional way to implement memoization. Remembering the results in a purely functional way is possible, which can be found in memoize package in Haskell. Following is an example:

(define (memoize f)
  (define results (stream-map f (in-naturals)))
  (lambda (n) (stream-ref results n)))

(define fib
  (memoize
   (λ (n)
     (cond [(= n 0) 1]
           [(= n 1) 1]
           [else (+ (fib (- n 1))
                    (fib (- n 2)))]))))

I'm a newbie to the racket programming language. So any suggestions and PR are welcomed.

pdcxs/leetcode-racket

Purely Functional Solutions of LeetCode Problems