leetcode/solution/0800-0899/0858.Mirror Reflection/Solution.java

class Solution {
    public int mirrorReflection(int p, int q) {
        int g = gcd(p, q);
        p = (p / g) % 2;
        q = (q / g) % 2;
        if (p == 1 && q == 1) {
            return 1;
        }
        return p == 1 ? 0 : 2;
    }

    private int gcd(int a, int b) {
        return b == 0 ? a : gcd(b, a % b);
    }
}