Implement int sqrt(int x).

Compute and return the square root of x.

    public int sqrt(int x) {
        if (x  <= 1) {
            return x;
        }
        int start = 0;
        int end = x;
        while (start <= end) {
            int median = start + (end - start) / 2;
            int temp = x / median;
            if (temp == median) {
                return median;
            } else if(temp < median) {
                end = median - 1;
            } else {
                start = median + 1;
            }
        }
        return end;
    }