刷题-String to Integer (atoi)缺python

Implement atoi to convert a string to an integer.

Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases.

Notes: It is intended for this problem to be specified vaguely (ie, no given input specs). You are responsible to gather all the input requirements up front.

public class Solution {

    private static final int maxDiv10 = Integer.MAX_VALUE / 10;
    public int atoi(String str) {
        int n = str.length();
        int i = 0;
        while (i < n && Character.isWhitespace(str.charAt(i))) i++;
        int sign = 1;
        if (i < n && str.charAt(i) == '+') {
            i++;
            } 
        else if (i < n && str.charAt(i) == '-') {
          sign = -1;
          i++;
       }
       int num = 0;
       while (i < n && Character.isDigit(str.charAt(i))) {
          int digit = Character.getNumericValue(str.charAt(i));
          if (num > maxDiv10 || num == maxDiv10 && digit >= 8) {
             return sign == 1 ? Integer.MAX_VALUE : Integer.MIN_VALUE;
          }
          num = num * 10 + digit;
          i++;
       }  
       return sign * num;
        
    }
}