From 44585ed339356d273c9af716d5f82f6a1a928efd Mon Sep 17 00:00:00 2001
From: Ian Roddis <gitlab@ie2r.com>
Date: Wed, 2 Jun 2021 13:55:12 -0300
Subject: [PATCH] Shortest path found

---
 daggy/include/daggy/DAG.hpp | 50 ++++++++++++-------------------------
 tests/unit_dag.cpp          | 18 ++++++++++---
 2 files changed, 30 insertions(+), 38 deletions(-)

diff --git a/daggy/include/daggy/DAG.hpp b/daggy/include/daggy/DAG.hpp
index ab6162e..75a9272 100644
--- a/daggy/include/daggy/DAG.hpp
+++ b/daggy/include/daggy/DAG.hpp
@@ -1,56 +1,38 @@
 #pragma once
 
+#include <deque>
 #include <stdexcept>
 #include <unordered_map>
 #include <unordered_set>
 
 namespace daggy {
-
-    template<typename I, typename T>
+    template<typename T>
     class DAG {
         public:
             DAG() {}
 
-            void addVertex(I id, T && data);
-            void dropVertex(I id);
-            void updateVertex(I id, T && data);
+            void addVertex(T id);
+            void dropVertex(const T & id);
 
-            void addEdge(I src, I dst);
-            void dropEdge(I src, I dst);
+            void addEdge(const T & src, const T & dst);
+            void dropEdge(const T & src, const T & dst);
+
+            // Returns the path from {from} to {to}
+            std::deque<T> shortest_path(const T & from, const T & to);
 
         private:
             struct Vertex {
-                T data;
-
                 // It's a bit redundant to preserve both, but
-                // it makes it possible to traverse both ways as
-                // needed.
-                std::unordered_set<I> parents;
-                std::unordered_set<I> children;
+                // it makes it possible with and against the
+                // directions possible
+                std::unordered_set<T> parents;
+                std::unordered_set<T> children;
             };
 
-            std::unordered_map<I, Vertex> vertices;
+            std::unordered_map<T, Vertex> vertices;
+            std::unordered_set<T> roots;
     };
 
-    template<typename I, typename T>
-    void DAG<I,T>::addVertex(I id, T && data) {
-        vertices.emplace(id, Vertex{std::move(data), {}});
-    }
+#include "DAG.impl"
 
-    template<typename I, typename T>
-    void DAG<I,T>::addEdge(I from, I to) {
-        auto src = vertices.find(from);
-        if (src == vertices.end())
-            throw std::runtime_error("Invalid from during edge insertion");
-        auto dst = vertices.find(to);
-        if (dst == vertices.end())
-            throw std::runtime_error("Invalid dst during edge insertion");
-
-        // ensure that no cycles are introduced
-
-
-        // Add the edge
-        src->second.children.insert(to);
-        dst->second.parents.insert(from);
-    }
 }
diff --git a/tests/unit_dag.cpp b/tests/unit_dag.cpp
index ecc1cc6..493790d 100644
--- a/tests/unit_dag.cpp
+++ b/tests/unit_dag.cpp
@@ -5,10 +5,20 @@
 #include "catch.hpp"
 
 TEST_CASE("DAG Basic Tests", "[dag]") {
-    daggy::DAG<int, std::string> dag;
+    daggy::DAG<int> dag;
 
-    dag.addVertex(0, "hello");
-    dag.addVertex(1, "goodbye");
+    dag.addVertex(0);
+    for (int i = 1; i < 10; ++i) {
+      dag.addVertex(i);
+      dag.addEdge(i-1, i);
+    }
 
-    dag.addEdge(0, 1);
+    dag.addEdge(5, 9);
+
+    auto sp = dag.shortest_path(1,9);
+    std::cout << "Shortest path from 1 to 10: (";
+    for (auto k : sp) {
+      std::cout << k << " -> ";
+    }
+    std::cout << std::endl;
 }