Project Euler Problem 4

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问题：

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.

思路：

求出两个三位数的乘积，然后判断该乘积是否为回文数，最后找出最大的回文数

Code in Python:

import timestart = time.time()def palindromeNum(s):    '''If s is a palindrome number,return true.'''    s = str(s)    temp = s[::-1]#字符串反转    if s == temp:        return(True)    else:        return(False)largest = 0       for first in range(100,1000):    for second in range(first + 1,1000):        temp = first * second        if palindromeNum(temp):            if largest < temp:                largest = tempfinish = time.time()print('The largest palindrome',largest,'is found in',finish - start,'seconds')

Solution:

The largest palindrome906609 is found in 0.34902000427246094 seconds