04 May 9. Palindrome Number
Given an integer x, return true if x is palindrome integer.
An integer is a palindrome when it reads the same backward as forward. For example, 121 is palindrome while 123 is not.
Example 1:
Input: x = 121 Output: true
Example 2:
Input: x = -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: x = 10 Output: false Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Example 4:
Input: x = -101 Output: false
Constraints:
-231 <= x <= 231 - 1
python
class Solution:
def isPalindrome(self, x: int) -> bool:
if x < 0:
return False
origin = x
revert_value=0
while origin:
revert_value = revert_value * 10 + origin%10
origin = origin//10
if(revert_value> pow(2,31)):
return False
if(x == revert_value):
return True
else:
return False
class Solution:
def isPalindrome(self, x: int) -> bool:
if x<0:
return False
inputNum = x
outputNum = 0
while x>0:
outputNum = outputNum * 10 +x % 10
x = x // 10
return inputNum == outputNum
class Solution:
def isPalindrome(self, x: int) -> bool:
if x<0 or (x > 0 and x%10 == 0):
return False
left = x
right = 0
while left > right:
right = right * 10 +x % 10
left = left // 10
print(right)
print(left)
print(‘————‘)
if (left == right) or (left == (right // 10)):
return True
else:
return False
No Comments