Add Graph interface

Author: rabestro

.idea/compiler.xml

@@ -0,0 +1,16 @@
+package algorithm;
+
+import java.util.List;
+import java.util.Map;
+
+public interface Graph<T> extends Map<T, Map<T, Number>> {
+
+    default double getDistance(List<T> path) {
+        double distance = 0;
+        for (int i = 1; i < path.size(); ++i) {
+            final var previous = this.get(path.get(i - 1));
+            distance += previous.get(path.get(i)).doubleValue();
+        }
+        return distance;
+    }
+}