problems: add mirror reflection

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/mirror-reflection.cpp

@@ -0,0 +1,18 @@
+class Solution {
+public:
+    int mirrorReflection(int p, int q)
+    {
+        auto lcm = p * q / std::gcd(p, q);
+        auto x = lcm / p;
+        auto y = lcm / q;
+
+        if (x % 2 == 0) {
+            return 0;
+        }
+
+        if (y % 2 == 0) {
+            return 2;
+        }
+        return 1;
+    }
+};