reward:
1. Review the regular expression, re.findall () returns the qualifying list
2. When comparing the size of global variables, or with a boundary value relates to the need to use flexible min max
3. Learn to * usage * can only be used in mass participation in
class Solution:
def myAtoi(self, str: str) -> int:
return min(max(int(*re.findall('^[+-]?\d+',str.lstrip())),-2**31),2**31-1)