https://adventofcode.com/2017/day/11

day_11.el

(defun read-file-as-string (file-path)
  (with-temp-buffer
    (insert-file-contents file-path)
    (mapcar 'string-trim (split-string (buffer-string) "," t))
    )
)

(defun calculate-dist (x y z)
  (/
   (+
    (abs x)
    (abs y)
    (abs z)
    )
   2)
  )

(defun hex-dist (lst)
  (let ((x 0) (y 0) (z 0) (max 0) dist)
    (dolist (step lst)
      (cond
       ((string= step "ne")
        (progn
          (setq x (1+ x))
          (setq z (1- z))
          )
        )
       ((string= step "se")
        (progn
          (setq x (1+ x))
          (setq y (1- y))
          )
        )
       ((string= step "s")
        (progn
          (setq z (1+ z))
          (setq y (1- y))
          )
        )
       ((string= step "sw")
        (progn
          (setq x (1- x))
          (setq z (1+ z))
          )
        )
       ((string= step "nw")
        (progn
          (setq x (1- x))
          (setq y (1+ y))
          )
        )
       ((string= step "n")
        (progn
          (setq y (1+ y))
          (setq z (1- z))
          )
        )
       )
      (setq dist (calculate-dist x y z))
      (when (> dist max) (setq max dist))
      )
    (print (calculate-dist x y z))
    (print max)
    )
  )

(hex-dist '("ne" "ne" "ne")) ;; 3
(hex-dist '("ne" "ne" "sw" "sw")) ;; 0
(hex-dist '("ne" "ne" "s" "s")) ;; 2
(hex-dist '("se" "sw" "se" "sw" "sw")) ;; 3

(hex-dist (read-file-as-string "./input.txt"))
(read-file-as-string "./input.txt")