Emacs Lisp experimentations

gistfile1.el

(defun project-euler-1 (n)
  "Implementation for Project Euler 1"
  (let ((sum 0))
    (dotimes (i n)
      (if (or (= 0 (% i 3)) (= 0 (% i 5)))
          (setq sum (+ sum i))))
    sum))
(project-euler-1 1000)

(defvar memoize (make-hash-table :test 'equal))

(defun fibonacci (n)
  "Implementation for Project Euler2"
  (let (memoized)
    (setq memoized (gethash (number-to-string n) memoize))
    (if memoized
        (progn
          memoized)
      (cond ((= n 1) 1)
            ((= n 0) 1)
            ((setq return-value (+ (fibonacci (- n 1))(fibonacci (- n 2))))
             (puthash (number-to-string n) return-value memoize)
             return-value)))))

(defun project-euler-2 (n)
  (let ((sum 0)
        (i 1)
        (flag t))
    (while flag 
      (setq val (fibonacci i))
      (if (> val n)
          (setq flag nil)
        (progn
          (if (= 0 (% val 2))
              (setq sum (+ sum val)))))
      (setq i (+ i 1)))
    sum))

(fibonacci 10)
(project-euler-2 4000000)


(apply '+ (remove-if-not #'(lambda (x) (zerop (mod x 2))) '(1 2 3 4 5 6 7 8 9 10)))

(apply '+ (remove-if-not #'(lambda (n) (or (zerop (mod n 3)) (zerop (mod n 5)))) (number-sequence 1 999)))

       (number-sequence 1 10)
       
(defun fizzbuzzp (n)
  (or (zerop (mod n 3)) (zerop (mod n 5))))
(loop for i from 1 to 999 when (fizzbuzzp i) summing i)


(remove-if #'(lambda (f) (or (string= "." f) (string= ".." f))) (directory-files "."))


(loop with product = '()
      for i from 1 to 10 
      do (loop for j from 1 to 10 do (push (* i j) product))
      finally return (nreverse product))
(print  product)

gistfile2.el

(require 'cl)

(defun square (n)
  (* n n))

(defun pythagorian (a b c)
  (= (square c) (+ (square b) (square a))))

(apply '* (loop named outer for a from 1 to 1001
                do (loop for b from a to 1001 do
                         (if (pythagorian a b (- (- 1000 a) b))
                             (return-from outer (list a b (- (- 1000 a) b)))))))