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# Runtime: 69 ms (Top 20.00%) | Memory: 13.9 MB (Top 79.88%)
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class Solution:
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    def assign_sign(self, sign):
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        # verify that we haven't already got a sign
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        #  "+42-" -> we don't want to return -42; hence check
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        if not self.is_neg and not self.is_pos:
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            # no sign has been set yet
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            if sign == "+":
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                self.is_pos = True
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            elif sign == "-":
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                self.is_neg = True
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        return
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    def add_to_int(self, num):
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        if not self.num:
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            self.num = num
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        else:
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            self.num = (self.num * 10) + num
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    def myAtoi(self, s: str) -> int:
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        #  remove the leading and trailing spaces
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        self.is_neg = False
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        self.is_pos = False
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        self.num = None
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        s = s.strip()
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        for i in s:
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            # ignore the rest of the string if a non digit character is read
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            if i in ("+", "-"):
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                #  only read the first symbol; break if second symbol is read
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                if self.is_pos or self.is_neg or isinstance(self.num, int):
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                    #  one of the two symbols is read or a number is read
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                    break
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                self.assign_sign(i)
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                continue
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            try:
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                i = int(i)
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                self.add_to_int(i)
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            except ValueError:
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                # it's neither a sign, nor a number; terminate
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                break
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        # outside the loop; compile the result
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        if not self.num:
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            return 0
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        upper_limit = 2**31 - 1
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        if self.is_pos or (not self.is_pos and not self.is_neg):
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            if self.num > upper_limit:
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                self.num = upper_limit
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        elif self.is_neg:
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            if self.num > upper_limit + 1:
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                self.num = upper_limit + 1
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            self.num = -1 * self.num
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        return self.num