# 9. Palindrome Number

## 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