;;; https://gitlab.com/Syndamia/senzill
(require :senzill)
(use-package :senzill.math)
(use-package :senzill.collections)
(use-package :senzill.io)

(ask-for-stream (prog-input)
  (let ((forest '()))
    (doread-lines (inpt :read-line-options (prog-input NIL))
                  (push-back (map 'list
                                  (lambda (x) (cons x 1)) ; Each tree is a (cons) pair of (<TREE_HEIGHT> . <SCENIC_SCORE>)
                                  (integer-to-list (parse-integer inpt)
                                                   :min-length (length (first forest)))) ; Doesn't handle if very first digit(s) is zero
                             forest))

    (defun loop-on-row (row)
      (loop for col on row
            maximize (car (first col)) into max-height
            while (cdr col) 
            do
            (*= (cdr (first col))
                ;;; Counts seen trees on the right of the current tree
                (loop for seen on (cdr col)
                      count T into result
                      while (and col (> (car (first col)) (car (first seen))))
                      finally (return result)))
            finally (setf (cdr (first col)) 0))) ; Last tree doesn't see any trees

    ;;; Checks every row
    (loop for row in forest
          do
          ;; Iterate from left to right
          (loop-on-row row)
          ;; Iterate from right to left
          (loop-on-row (reverse row)))

    ;;; Checks every column
    (loop for i from 0 to (- (length (first forest)) 1)
          for col = (loop for row in forest
                          collect (nth i row))
          do
          ;; Iterate top to bottom
          (loop-on-row col)
          ;; Iterate bottom to top
          (loop-on-row (reverse col)))

    (loop for row in forest
          maximize (loop for tree in row
                         maximize (cdr tree)) into result
          finally (print result))))