Krdytkyu

I was given a question in an interview which is as follows.

Two input files are given

The first contains |N| ratios in the form of two labels and a ratio:



-------------------- ratios.csv --------------------

USD, GBP, 0.69

Meter, Yard, 1.09

YEN, EUR, 0.0077

GBP, YEN, 167.75

Horsepower, Watt, 745.7



Each line A, B, C means that C is a conversion factor from A to B.  In other words, multiply by C to go from A to B, and 1 A is worth C B's.





Example: USD, GBP, 0.69 means that 1 USD = 0.69 GBP, so multiplying by 0.69 converts an amount from USD to GBP. 



The second file contains |M| queries in the form of two labels

-------------------- queries.csv --------------------

USD,EUR

Yard,Meter

....

-----------------------------------------------------



And the expected output is a file with the query and the ratio value filled in.

-------------------- output.csv --------------------

USD, EUR, 0.89

Yard, Meter, 0.91

....

-----------------------------------------------------



Challenge: Write a program that reads both input files and produces the expected output file

and the answer I provided within (30 mns)

class Solution:

   def __init__(self):

    self.util_dict={}

    self.util_dict.update({‘USD’:[((0.69), GBP)]})          

    self.util_dict.update({‘GBP’:[((1/0.69),USD),(167, YEN)]})

    self.util_dict.update({‘EUR’:[(1/0.0077,YEN)]})

    self.util_dict.update({‘YEN’:[(1/167,GBP),(0.0077,EUR)]})

    self.util_dict.update({‘METER’:[(1.09,Yard)]})

    self.util_dict.update({‘YARD’:[((1/1.09), Meter)]})





    # USD,EUR

    def calculateConv(self,qt1,qt2):

        # input format [qt1,0]

        visited=set()

        q.append(qt1)

        ans=1

        count=0

        while q:

         k=q.pop() # USD

         if k[0] in visited:

           continue

         if k==qt2:

            ans*=k[1]

            break

         if count>1:

            ans*=k[1] #0.69*167

         if k in self.util_dict:

            count+=1

            keys=self.util_dict[qt1]

            visited.add(k)

            for c in range(keys):

              q.append(c)



         return ans

The idea is to save all the conversion factors in a dictionary. i.e if USD to GBP is 0.69 then GBP to USD is (1/0.69).
Loop through the values of key (USD) and multiply the value till we find the second quantity while keeping a track of visited keys.

is this solution not optimized or is there a better way to code this problem ? I understand there are bugs which I pointed out but what I want to know is is this approach wrong ?