class Solution {
    public int divide(int dividend, int divisor) {
        if(dividend == -2147483648 && divisor == -1){
            return 2147483647;
        }
        if(divisor == 1){
            return dividend;
        }
        if(divisor == -1){
            return -dividend;
        }
        boolean flag = true;
        if(dividend < 0 && divisor > 0 || dividend > 0 && divisor < 0){
            flag = false;
        }
        int LIMIT = -1073741824;
        int a = dividend < 0 ? dividend : -dividend;
        int b = divisor < 0 ? divisor : -divisor;
        int res = 0;
        while(a <= b){
            int c = b,d = -1;
            while(c >= LIMIT && d >= LIMIT && c >= a - c){
                c += c;
                d += d;
            }
            a -= c;
            res += d;
        }
        return flag ? -res : res;
    }
}

class Solution {
    public int[] countBits(int n) {
        int[] res = new int[n + 1];
        for (int i = 0; i < n + 1; i++) {
            res[i] = Integer.bitCount(i);
        }
        return res;
    }
}