CodingBat Python make_chocolate code failing in "other tests"

Question

There is a coding problem on CodingBat.com (Logic-2 Python section) that asks for a function to determine how many small chocolate bars are used for a weight requirement. The question is as follows:

We want make a package of goal kilos of chocolate. We have small bars (1 kilo each) and big bars (5 kilos each). Return the number of small bars to use, assuming we always use big bars before small bars. Return -1 if it can’t be done.

make_chocolate(4, 1, 9) → 4
make_chocolate(4, 1, 10) → -1
make_chocolate(4, 1, 7) → 2

I came up with this solution to the problem but it still fails in “other tests”. Is there any problem that causes this?

Code:

def make_chocolate(small, big, goal):
    if (small + 5*big < goal) or (goal % 5 > small):
        return -1

    elif small >= goal:
        return small
    else:
        smallnum = 0
        for i in range(1,big+1):
            if 5*i + small >= goal:
                if 5*i > goal:
                    break
                smallnum = goal - 5*i
        return smallnum

EDIT:
I have managed to finish the problem thanks to Mariah Akinbi. I have updated the code as follows:

def make_chocolate(small, big, goal):
    if (small + 5*big < goal) or (goal % 5 > small):
        return -1

    elif 5 <= goal:
        smallnum = 0
        for i in range(1,big+1):
            if 5*i + small >= goal:
                if 5*i > goal:
                    break
                smallnum = goal - 5*i
        return smallnum
  return goal

Asked By: Karma Cool

||

Source

Answer 1

Your code seems to fail on:

make_chocolate(8,1,7)–> returns 8 instead of 2

I believe the issue is:

elif small >= goal:
    return small

The instructions say to use the big bars first, then use the nuggets to meet the goal.

Answered By: Mariah Akinbi

Answer 2

Here is much simpler solution:

def make_chocolate(small, big, goal):
  big_use = min(goal / 5, big)
  small_needed = goal - big_use * 5
  if small < small_needed:
    return -1
  return small_needed

Answered By: Alex Black

Answer 3

see my code below

def make_chocolate(small, big, goal):
    if goal-big*5<=small:  #find out if the total chocolate can make the goal
      if goal%5==0 and goal-big*5==0: # if small bars not required
        return 0
      if goal-big*5>0: 
        return goal-big*5
      if goal-big*5<0 and goal%5<=small:
        return goal%5
      else:
        return -1
      
    if goal-big*5>small:
      return -1

Answered By: John

Answer 4

A Simpler Approach

def make_chocolate(smallBars, bigBars, goal):

    bigBarsInKilo =  bigBars * 5

    while bigBarsInKilo > goal:
        bigBarsInKilo -= 5

    smallBarsRequired = goal - bigBarsInKilo

    if smallBars >= abs(smallBarsRequired): # abs (to ignore negative values)
        return smallBarsRequired
    else:
        return -1

print(make_chocolate(1, 2, 5))

Answered By: Yash Marmat

Answer 5

def make_chocolate(small, big, goal):
  if goal> big*5 +small or goal % 5 > small:
    return -1
  elif big *5 > goal:
    return goal % 5
  else:
    return goal - big *5

Answered By: Hooman Tay

CodingBat Python make_chocolate code failing in "other tests"

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