Initial data commit

Task/Fibonacci-sequence/Java/fibonacci-sequence-4.java

@@ -0,0 +1,18 @@
+public class Fibonacci {
+
+    static final Map<Integer, Long> cache = new HashMap<>();
+    static {
+        cache.put(1, 1L);
+        cache.put(2, 1L);
+    }
+
+    public static long get(int n)
+    {
+        return (n < 2) ? n : impl(n);
+    }
+
+    private static long impl(int n)
+    {
+        return cache.computeIfAbsent(n, k -> impl(k-1) + impl(k-2));
+    }
+}