day03.scm

(module day03
  (include "utils.scm")
  )

(define (calculate-expt-base a)
  (if (eq? 0 (modulo a 2))
    (+ a 1)
    a
    )
  )
(define (calculate-a x)
  (inexact->exact (ceiling (sqrt x)))
  )
(define (calculate-ring exponent-base)
  (/ (+ exponent-base 1) 2)
  )
(define (calculate-items-in-ring ring)
  (- (expt ring 2) (expt (- ring 2) 2))
  )
(define (calculate-items-per-side items-in-ring)
  (+ 1 (/ items-in-ring 4))
  )
(define (calculate-beginning-of-ring items-per-side items-in-ring)
  (+ (- (expt items-per-side 2) items-in-ring) 1)
  )
(define (calculate-index-in-ring x beginning-of-ring)
  (- x beginning-of-ring)
  )
(define (calculate-index-for-side index-in-ring items-per-side)
  (modulo index-in-ring (- items-per-side 1))
  )
(define (calculate-horizontal-distance-to-center-of-side index-for-side ring)
  (abs (- index-for-side (- ring 2)))
  )
(define (total-distance horizontal-distance ring)
  (+ horizontal-distance (- ring 1))
  )
; -------------
(define (calculate-with-x-ring-items-in-ring-items-per-side x ring items-in-ring items-per-side)
  (total-distance
    (calculate-horizontal-distance-to-center-of-side
      (calculate-index-for-side
        (calculate-index-in-ring x
          (calculate-beginning-of-ring items-per-side items-in-ring)
          ) items-per-side)
      ring)
    ring)
  )

(define (calculate-with-x-ring-items-in-ring x ring items-in-ring)
  (calculate-with-x-ring-items-in-ring-items-per-side x ring items-in-ring
    (calculate-items-per-side items-in-ring))
  )

(define (calculate-with-x-ring-expt-base x ring expt-base)
  (calculate-with-x-ring-items-in-ring x ring (calculate-items-in-ring expt-base))
  )
(define (calculate-with-x-expt-base x expt-base)
  (calculate-with-x-ring-expt-base x (calculate-ring expt-base) expt-base)
  )
(define (do-manhattan-dist x)
  (if (eq? 1 x)
    0
    (calculate-with-x-expt-base x (calculate-expt-base (calculate-a x)))
    )
  )
(define (manhattan-dist lst)
  (if (null? lst)
    '()
    (begin
      (display (do-manhattan-dist (string->integer (car lst))))
      (display " ")
      (manhattan-dist (cdr lst))
      )
    )
  )

(define (day3 in)
  (manhattan-dist in)
  (display " <- part 1\n")
  )

(day3 (string-split (read-string (open-input-file "day03in.txt")) "\n"))