Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
Example 1:
Input: 121
Output: true
Example 2:
Input: -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
Example 3:
Input: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Follow up:
Coud you solve it without converting the integer to a string?
Solution1:
class Solution(object):
def isPalindrome(self, x):
"""
:type x: int
:rtype: bool
"""
if x < 0: return False
else:
s = str(x)
l = len(s)
for ss in s:
if ss != s[l-1]:
return False
l -= 1
return True
Solution2:
class Solution(object):
def isPalindrome(self, x):
"""
:type x: int
:rtype: bool
"""
if (x < 0) or (x != 0 and x%10 == 0): return False
y = 0
while x > y:
y = y*10 + x%10
x = x/10
if (x == y) or (y/10 == x): return True
else: return False
