String - 8. String to Integer (atoi)

#===================================
# Tanzila Islam
# Email: tanzilamohita@gmail.com
# Language: Python 3
#===================================

class Solution:
    def myAtoi(self, s: str) -> int:
        s = s.strip()
        if len(s) == 0: return 0
        res = 0
        sign = 1
        flag = 0

        if s[0] == '-':
            sign = -1
       
        for i in range(len(s)):
            if s[i].isnumeric():
                res = res*10+(ord(s[i])-ord('0'))
                flag = 1
            elif (s[i] == "+" or s[i] == "-") and (flag == 0):
                flag = 1
                pass
            else:
                break
        
        res = res*sign
        if res in range((-2**31), (2**31)-1):
            return res
        elif res<0: 
            return -2**31
        else: 
            return 2**31-1