02-2021-01-11leetcode

7.整数翻转

class Solution:
    def __reversed__(self, x:int)->int:
        int_max = 2**31-1
        int_min = -(2**31)
        rev = 0
        while x:
            pop = x%10 if x>0 else x%-10
            x = x//10 if x>0 else int(x/10)
            if rev>int_max or (rev == int_max and pop>7):
                return 0
            if rev<int_min or (rev ==int_min and pop <-8):
                return 0
            return rev

8. 字符串转换整数 (atoi)

class Solution:
    def myAtoi(self, s: str) -> int:
        return max(min(int(*re.findall('^[\+\-]?\d+', s.lstrip())), 2**31 - 1), -2**31)

9.回文数

class Solution:
    def isPalindrome(self, x: int) -> bool:
        return True if str(x) == str(x)[::-1] else False