Question

Hello, can someone help me with my code about Ps2 Diophantine equations? I am stuck at the problem 4. When I run my code, it just keeps going on and on and never gives me any output. I have to press ctrl+c to stop. Here is my code: http://bpaste.net/show/53890/ I cannot figure out what is wrong. Can somebody help me with my code? Thank you.

Answer 1

the code is ok - try putting a print(a,b,c,n) before the break statement. the break only exits the bottom loop, for c, but continues for a and for b. test it with n in range(10), for example, and x=1, y=2, z=3. you may want to print solutions rather than bestSoFar, but play with it.

Answer 2

Your code is probably running just fine. The trouble is that with 4 nested loops, each going up to 200, you're doing somewhere in the area of 200**4 iterations. That takes a while, quite possibly hours, to run. This is something to keep in mind when your designing your algorithm.

Answer 3

Thank you, guys. Yes, my code is, indeed, running fine. Can I ask whether there is a way of break out all nested loops? I can only think of using this 4 nested loops to solve this problem set. Is there any other efficient way? Some hints?

Answer 4

try
found = False
for a in range(n):
if found:
break
for b...
if found:
break
for c.....
if <condition> :
do stuff
found = True
break

Answer 5

you can make it somewhat more efficient:
for a in range(n):
if a*x > n: # adding more won't help
break
for b in range(n):
if a*x + b*x > n:
break
for c....