数据结构算法操作试题(C++/Python)——字符串转换整数 (atoi)

class Solution:
    def myAtoi(self, str):
        """
        :type str: str
        :rtype: int
        """
        str = str.strip()
        if not str:
            return 0
        returnStr = ""
        if self.judgeInt(str[0], 1):
            returnStr = str[:1]
            for i in range(1,len(str)):
                if self.judgeInt(str[i], 0):
                    returnStr = str[:i+1]
                else:
                    returnStr = str[:i]
                    break
            try:
                returnStr = int(returnStr)
                return self.intRange(returnStr)
                #self.intRange(returnStr)
            except:
                print("step_2")
                print(returnStr)
                return 0
        else:
            return 0
        
    def judgeInt(self, s, first_flag):
        try:
            s = int(s)
            return True
        except:
            print("step_1")
            if s == '-' or s == '+' :
                if first_flag:
                    return True
                else:
                    return False
            else:
                return False
            
    def intRange(self, i):
        i = int(i)
        if i > (2**31-1):
            return 2**31-1
        elif i < (-2**31):
            return -2**31
        else:
            return i

class Solution:
    # @return an integer
    def myAtoi(self, str):
        str = str.strip()
        str = re.findall('(^[+-0]*d+)D*', str)

        try:
            result = int(''.join(str))
            MAX_INT = 2147483647
            MIN_INT = -2147483648
            if result > MAX_INT > 0:
                return MAX_INT
            elif result < MIN_INT < 0:
                return MIN_INT
            else:
                return result
        except:
            return 0