Debugging Code: Finding Ramanujan Numbers Using 2 While Loops

Question

I'm trying to find, using dictionaries:

1. Using two while loops, nested, create a dictionary whose keys are the sum of two cubes. That is iterate through all pairs i and j, calculating i^3+j^3 until it gets too large.

   2.Whenever you calculate a new i^3+j^3, check and see if there is already an entry for it.

   3.If so, you have found a new pair of numbers the sum of whose cubes, because there is already a pair of number that cube and sum to the same value.

Here is my code: please help me figure what is wrong with my code.

dit = dict()
j = 1
i = 1
while i < 10:

    while j < 10:
        summ = i**3+ j**3

        if summ in dit:

           print(summ, (i,j), dit.get(summ))

        else:
            dit [summ] = (i,j)
    j = j +1
    print(dit)

j = 2
i = i + 1

Answer 1

You aren't modifying your variables from within your while loop, so the condition never changes. You need to change your indentation a little so that it works.

dit = dict()
j = 1
i = 1
while i < 10:

    while j < 10:
        summ = i**3+ j**3

        if summ in dit:

           print(summ, (i,j), dit.get(summ))

        else:
            dit [summ] = (i,j)
        j = j +1
        print(dit)

    j = 2
    i = i + 1

Answer 2

its easy to just generate unique values from the start by creating a 'trianglular outer product' with nested for:
for a in range(1, c//2+1) for b in range(c//2,c)

c = 5
d = [(a**3 + b**3, (a, b)) for a in range(1, c//2+1) for b in range(c//2,c)]

# test for uniqueness

len(d) == len(set(d))
True

d
[(9, (1, 2)),
 (28, (1, 3)),
 (65, (1, 4)),
 (16, (2, 2)),
 (35, (2, 3)),
 (72, (2, 4))] 

d.sort()
d
[(9, (1, 2)),
 (16, (2, 2)),
 (28, (1, 3)),
 (35, (2, 3)),
 (65, (1, 4)),
 (72, (2, 4))]