Project Euler, palindrome problem, not getting intended answer, python

Question

1.00/5 (1 vote)

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SQL

a = []
b = []
for x in range (101, 999):
    for y in range (101, 199):
        z = x * y
        a.append(z)
def reverse(n):
    n = str(n)
    if n == n[::-1]:
        n = int(n)
        b.append(n)
    return b

for number in a:
    reverse(number)

print max(b)

My result is 180181 but it should be 906609.

The original problem was:

"A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.

Find the largest palindrome made from the product of two 3-digit numbers."

Posted 19-Nov-14 5:01am

Member 11243554

Updated 19-Nov-14 5:06am

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CPallini · Accepted Answer · 2014-11-19T06:03:00

Solution 1

I would keep it simple:

Python

m = 0
for x in range (100, 999):
  for y in range (100, 999):
    z = x*y
    n = str(z)
    if n == n[::-1]:
      if  m < z:
        m = z

print(m)

Posted 19-Nov-14 6:03am

CPallini

Comments

Member 11243554 19-Nov-14 12:07pm

Thanks for the solution but I was more looking for the problem in my code i.e. why my code ain't working? What's wrong with it?

CPallini 19-Nov-14 13:25pm

Your code doesn't work because the upper limit of the inner for loop is wrong (it should be 999).