#lang racket
(define (schet lst_int lst_func)
      (car (lst_schet (rec_mult lst_int (mult lst_func '() 0))
                      (filter (λ(x) (not (eq? (eval x) *))) lst_func))))
;\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
(define (lst_schet lst_int lst_func)
  (if (empty? (cdr lst_int))
              lst_int
  (lst_schet (append (list ((eval (car lst_func)) (car lst_int) (cadr lst_int))) (cddr lst_int)) (cdr lst_func))))
;\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
(define (mult lst_func res pos) ;( pos1 pos2 ) (* * *) ( 0 1 2 )
  (if (empty? lst_func)
      res
      (if (eq? (eval (car lst_func)) *)
          (mult (cdr lst_func) (append res (list pos)) (+ pos 1))
          (mult (cdr lst_func) res (+ pos 1)))))
;\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
(define (rec_mult lst_int lst_mult) ;( 1 6 4) (1)
  (if (empty? lst_mult)
      lst_int
      (rec_mult (append
                 (take lst_int (car lst_mult))
                 (list (* (list-ref lst_int (+ (car lst_mult) 1))(list-ref lst_int (car lst_mult))))
                 (drop lst_int (+ (car lst_mult) 2)))
                (cdr (map (λ (x) (- x 1)) lst_mult)))))

(define (perenos lst lst2 f)
  (if (empty? lst)
      lst2
      (if (not f)
      (begin (display (append lst2 lst)) (append lst2 lst) )
      (cond [(eq? (eval (car lst)) *) (perenos (cdr lst) (append lst2 (list '+))
                                               (if (empty? (cdr lst))
                                                          #f
                                                          #t))]
            [(eq? (eval (car lst)) +) (perenos (cdr lst) (append lst2 (list '-)) #f)]
            [(eq? (eval (car lst)) -) (perenos (cdr lst) (append lst2 (list '*)) #f)]))))

(define (near_zero lst-main)
  (define end (build-list (- (length lst-main) 1) (λ (x) '+)))
  (define res (build-list (- (length lst-main) 1) (λ (x) '+)))
    (define (SIGN lst)
    (if (equal? lst end)
        (help '() lst)
    (begin (help '() lst) (SIGN (perenos lst '() #t)))))
;(define lst-main '(1 2 3 5))

(define (help fix-lst lst)
    (if (empty? lst)
        (cond [(< (abs (schet lst-main fix-lst)) (abs (schet lst-main res)))
               (begin (display 1)(display fix-lst)(display 2) (display res)(set! res fix-lst)(display 3)(display fix-lst)(display 4) (display res))])
        (for-each (λ (x) (help (cons x fix-lst) (remove x lst))) lst)))
 (SIGN (append (build-list (- (length lst-main) 2) (λ (x) '+)) (list '-)))
  res)