ホーム - Project Euler

Problem 2¶

#!r6rs
#!chezscheme

(import (chezscheme))

(define answer-2
  (let loop ((first 0) (second 1) (result 0))
    (let ((next (+ first second)))
      (cond
        [(< 4000000 next) result]
        [(even? next)
         (loop second next (+ result next))]
        [else (loop second next result)]))))

(printf "2: ~D~%" answer-2)