simplify path structure

1 files changed, 45 insertions, 0 deletions

diff --git a/src/com.example.portfolio3/com/example/portfolio3/AdjMapGraph.java b/src/com.example.portfolio3/com/example/portfolio3/AdjMapGraph.java
new file mode 100644
index 0000000..85e5d04
--- /dev/null
+++ b/src/com.example.portfolio3/com/example/portfolio3/AdjMapGraph.java
@@ -0,0 +1,45 @@
+package com.example.portfolio3;
+
+// origin: <https://moodle.ruc.dk/course/section.php?id=211877>
+
+import java.util.*;
+
+///  Adjecency Map Graph - A map from vertices to map of target vertex to edge
+class AdjMapGraph extends AbstractGraph {
+
+  /// foo
+  AdjMapGraph() {}
+
+  /// foo
+  private Map<Vertex, Map<Vertex, Edge>> outEdge = new HashMap<>();
+
+  /// foo
+  public void insertEdge(Vertex v1, Vertex v2, int w) {
+    Edge e = new Edge(v1,v2, w);
+    if (!outEdge.containsKey(e.from()))
+      outEdge.put(e.from(), new HashMap<Vertex, Edge>());
+    outEdge.get(e.from()).put(e.to(), e);
+  }
+
+  /// foo
+  public Collection<Edge> edges() {
+    Set<Edge> edges = new HashSet<>();
+    for (Vertex v : outEdge.keySet())
+      for (Vertex w : outEdge.get(v).keySet())
+        edges.add(outEdge.get(v).get(w));
+    return edges;
+  }
+
+  /// foo
+  public Collection<Edge> outEdge(Vertex v) {
+    return outEdge.get(v).values();
+  }
+
+  /// foo
+  public Integer getWeight(Vertex v1, Vertex v2) {
+    // constant time operation
+    if(!outEdge.containsKey(v1))return null;
+    if(!outEdge.get(v1).containsKey(v2))return null;
+    return outEdge.get(v1).get(v2).weight();
+  }
+}