// https://leetcode.com/problems/string-to-integer-atoi/

class Solution {

    public int myAtoi(String s) {
        if (s == null || s.length() == 0) {
            return 0;
        }

        var chars = s.toCharArray();

        var reading_pointer = 0;
        var charsLength = chars.length;

        while (reading_pointer < charsLength && chars[reading_pointer] == ' ') {
            reading_pointer += 1;
        }
        if (reading_pointer == charsLength) {
            return 0;
        }

        var sign = 1;
        if (chars[reading_pointer] == '-') {
            sign = -1;
            reading_pointer += 1;
        } else if (chars[reading_pointer] == '+') {
            sign = 1;
            reading_pointer += 1;
        }

        long answerLong = 0;
        while (reading_pointer < charsLength && Character.isDigit(chars[reading_pointer])) {
            var digit = chars[reading_pointer] - '0';
            answerLong = answerLong * 10 + digit;

            if (sign * answerLong >= Integer.MAX_VALUE) {
                return Integer.MAX_VALUE;
            } else if (sign * answerLong <= Integer.MIN_VALUE) {
                return Integer.MIN_VALUE;
            }

            reading_pointer += 1;
        }

        return sign * (int) answerLong;
    }
}