#!/usr/local/bin/chicken-csi -s
(import (chicken io)
        (chicken sort))

;; A simple take on part-1 in constant memory
(define (part-1)
  (let loop ((curr 0) (max_ 0) (line (read-line)))
    (if (eof-object? line)
        (max curr max_)
        (if (equal? line "")
            (loop 0 (max curr max_) (read-line))
            (loop (+ curr (string->number line)) max_ (read-line))))))

; (print (part-1))


;; For part 2, it's probably cleanest to jump straight to the "N" case

(define (subseq lst i)   ; there's def an egg for this
  (if (equal? i 0)
      '()
      (cons (car lst) (subseq (cdr lst) (sub1 i)))))

(define (condense-weights weights)
  (let loop ((curr 0) (condensed '()) (weights weights))
     (cond ((null? weights) (cons curr condensed))
           ((not (car weights))
            (loop 0 (cons curr condensed) (cdr weights)))
           (else (loop (+ curr (car weights)) condensed (cdr weights))))))

(let ((weights (map string->number (read-lines))))
  (print (apply +
                (subseq (sort (condense-weights weights) >) 3))))