Topic: ( Challenge ) How many 'carrys'?

[Mark]

It has been a long time since we have had a challenge around here. I hope this one keeps you occupied for a little while.

When you do addition you 'carry' the 1 if the total is greater than 9. For example if we add 109 and 209 we would have one 'carry';

  1  <- one 'carry'
109
209
---
318

Challenge:
given two integers return how many 'carrys' we have.

The attached file has a two integers per line, you can use it or user input.

Not my idea, it was borrowed.

P.S. Additional languages are allowed

[JohnK]

Oh good one. Im going to think about this one at lunch.

[VovKa]

Code: [Select]

(defun test (n1 n2)
  (if (or (zerop n1) (zerop n2))
    0
    (if (< 9 (+ (rem n1 10) (rem n2 10)))
      (1+ (if (= 9 (rem (/ n1 10) 10))
    (test (/ n1 10)
  (if (= 9 (rem (/ n2 10) 10))
    (/ n2 10)
    (1+ (/ n2 10))
  )
    )
    (test (1+ (/ n1 10)) (/ n2 10))
  )
      )
      (test (/ n1 10) (/ n2 10))
    )
  )
)


[gile]

Very nice Vovka !

[SomeCallMeDave]

Does it have to be a LISP solution?

I have been playing with Ruby and cobbled this one together

Code: [Select]

def count_the_carry(string1, string2)
  #assumes strings are same length and numeric
  array1 = string1.split(//).collect{|x| x.to_i}
  array2 = string2.split(//).collect{|x| x.to_i}
  sum_array = Array.new
  array1.size.times {|i| sum_array[i]=array1[i]+array2[i]}
  carry_count = 0
  sum_array.each {|x| carry_count += 1 if x >=10}
  carry_count
end

input_file = File.new("c:/jobs/random_ints.txt", "r" )
output_file = File.new("c:/jobs/counts.txt", "w")
while (line = input_file.gets)
   nums = line.split
   count = count_the_carry(nums[0], nums[1])
   output_file.write(count.to_s + "\n")
end
input_file.close
output_file.close



My answers are attached

[VovKa]

thanx gile
i'm sorry but there was a mistake in the routine
i hope now it's ok

[Mark]

Does it have to be a LISP solution?

P.S. Additional languages are allowed

Nope!

[SomeCallMeDave]

Thanks, Mark.

Not only did I not read the original post correctly, I posted a solution that doesn't work. 

There is a particular case where my algorithm fails.  I won't spoil everyone else's fun by post it now.

Back to the drawing board for me.  At least Ruby is fun to play with.

[Tuoni]

For example if we add 109 and 209 we would have one 'carry';

...

To me that's two carries... you carry once into the 10's column then once into the 100's column?  Am I alone in this?

[ElpanovEvgeniy]

Code: [Select]

(defun test1 (a b)
 (if (zerop a)
  0
  (+ (/ (+ (rem a 10) (rem b 10)) 10) (test1 (/ a 10) (/ b 10)))
 ) ;_  if
)

[ronjonp]

Code: [Select]

(defun test1 (a b)
 (if (zerop a)
  0
  (+ (/ (+ (rem a 10) (rem b 10)) 10) (test1 (/ a 10) (/ b 10)))
 ) ;_  if
)

That's slick :kewl:

[VovKa]

ElpanovEvgeniy,
(test1 89 11) -> 1
should be 2

[ElpanovEvgeniy]

To me that's two carries... you carry once into the 10's column then once into the 100's column?  Am I alone in this?

Code: [Select]

(defun test-lst (l)
 ;;;(test-lst '(250 250 259 259))
 (if (cdr l)
  ((lambda (a)
    (+ a (test-lst (cons a (vl-remove 0 (mapcar '(lambda (a) (/ a 10)) l)))))
    )
   (/ (apply '+ (mapcar '(lambda (a) (rem a 10)) l)) 10)
  )
  0
 ) ;_  if
)

[ElpanovEvgeniy]

ElpanovEvgeniy,
(test1 89 11) -> 1
should be 2

Correction:

Code: [Select]

(defun test1 (a b)
 (if (zerop a)
  0
  ((lambda (c) (+ c (test1 (/ (+ c a) 10) (/ b 10))))
   (/ (+ (rem a 10) (rem b 10)) 10)
  )
 ) ;_  if
)

[VovKa]

ElpanovEvgeniy,
(test1 99 11) -> 1
should be 2