0029. Divide Two Integers

class Solution {
    public int divide(int dividend, int divisor) {
        if (dividend == Integer.MIN_VALUE && divisor == -1) {
            return Integer.MAX_VALUE;
        }
        boolean negative = (dividend < 0 && divisor > 0) || (dividend > 0 && divisor < 0);
        int res = 0;
        long a = Math.abs((long) dividend);
        long b = Math.abs((long) divisor);
        int shift = 31;
        while (a >= b) {
            while (a < b << shift) {
                shift --;
            }
            a -= b << shift;
            res += 1 << shift;
            shift--;
        }
        return negative ? -res : res;
    }
}