Lc9

"""
tc O(lgN) sc O(lgN)
"""
class Solution:
    def isPalindrome(self, x: int) -> bool:
        if x < 0 :
            return False
        elif x == 0:
            return True 
        A = []
        while x > 0:
            A.append(x%10)
            x = x//10
        return A[::] == A[::-1]
            

"""
tc O(lgN)  sc O(1)
"""
class Solution:
    def isPalindrome(self, x: int) -> bool:
        if x < 0 or (x != 0 and x%10 == 0  ):
            return False
        reverted_num = 0 
        # only reverse half of the digits, so 1. to avoid overflow 2. to   
        while x > reverted_num: 
            reverted_num = 10 * reverted_num + x % 10 
            x  = x // 10
            # in case given x is odd digits, so use reverted_num//10 to remove middle number 
        return x == reverted_num or x == reverted_num//10