题目
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.
回文数两个方向读的是一样的。两个两位数相乘得到的最大的回文数是9009 = 91 × 99。
找出由两个三位数相乘的最大的回文数。
思路
先将范围在100-999的两个数的所有乘积结果放在列表中,再将其从大到小排序,循环判断每一个数是否为回文数。
代码实现(python)
from past.builtins import xrange
def ispalindromic(num):
num = str(num)
strlist = list(num)
strlist.reverse()
numreverse = ''.join(strlist)
if num == numreverse:
return True
else:
return False
if __name__ == '__main__':
l = [x * y for x in xrange(999, 99, -1) for y in xrange(999, 99, -1)]
l.sort(reverse=True)
for i in range(len(l)):
if ispalindromic(l[i]) is True:
print(l[i])
break