[cpp] Update weighted graph

+ totalWeight is now tracked for BFS & DFS traversals
+ Refactor graph search info structs

cpp/algorithms/graphs/object/lib-graph.hpp

@@ -63,8 +63,8 @@ enum Color {
   Black
 };
 
-// Information used in all searches
+// Information used in all searches tracked for each node
-struct SearchInfo {
+struct NodeInfo {
   // Coloring of the nodes is used in both DFS and BFS
   Color discovered = White;
 };
@@ -73,8 +73,8 @@ struct SearchInfo {
 /******************************************************************************/
 // BFS search information struct
 
-// Information that is only used in BFS
+// Node information that is only used in BFS
-struct BFS : SearchInfo {
+struct BFS : NodeInfo {
   // Used to represent distance from start node
   int distance = 0;
   // Used to represent the parent node that discovered this node
@@ -90,8 +90,8 @@ using InfoBFS = std::unordered_map<int, struct BFS>;
 /******************************************************************************/
 // DFS search information struct
 
-// Information that is only used in DFS
+// Node information that is only used in DFS
-struct DFS : SearchInfo {
+struct DFS : NodeInfo {
   // Create a pair to track discovery / finish time
   // + Discovery time is the iteration the node is first discovered
   // + Finish time is the iteration the node has been checked completely
@@ -119,7 +119,7 @@ public:
   // An alternate DFS that checks each node of the graph beginning at startNode
   InfoDFS DFS(const Node &startNode) const;
   // Visit function is used in both versions of DFS
-  void DFSVisit(int &time, const Node& startNode, InfoDFS &searchInfo) const;
+  void DFSVisit(int &time, const Node& startNode, InfoDFS &dfs) const;
   // Topological sort, using DFS
   std::vector<Node> TopologicalSort(const Node &startNode) const;
 

cpp/algorithms/graphs/templated/lib-graph.hpp

@@ -79,8 +79,8 @@ enum Color {
   Black
 };
 
-// Information used in all searches
+// Information used in all searches tracked for each node
-struct SearchInfo {
+struct NodeInfo {
   // Coloring of the nodes is used in both DFS and BFS
   Color discovered = White;
 };
@@ -89,9 +89,9 @@ struct SearchInfo {
 /******************************************************************************/
 // BFS search information struct
 
-// Information that is only used in BFS
+// Node information that is only used in BFS
 template <typename T>
-struct BFS : SearchInfo {
+struct BFS : NodeInfo {
   // Used to represent distance from start node
   int distance = 0;
   // Used to represent the parent node that discovered this node
@@ -107,8 +107,8 @@ template <typename T> using InfoBFS = std::unordered_map<T, struct BFS<T>>;
 /******************************************************************************/
 // DFS search information struct
 
-// Information that is only used in DFS
+// Node information that is only used in DFS
-struct DFS : SearchInfo {
+struct DFS : NodeInfo {
   // Create a pair to track discovery / finish time
   // + Discovery time is the iteration the node is first discovered
   // + Finish time is the iteration the node has been checked completely
@@ -125,7 +125,7 @@ template <typename T> using InfoDFS = std::unordered_map<T, struct DFS>;
 // Edges stored as multimap<weight, pair<nodeA.data_, nodeB.data_>>
 template <typename T> using Edges = std::multimap<int, std::pair<T, T>>;
 
-struct MST : SearchInfo {
+struct MST : NodeInfo {
   int32_t parent = INT32_MIN;
   int rank = 0;
 };

cpp/algorithms/graphs/weighted/graph.cpp

@@ -156,11 +156,19 @@ int main (const int argc, const char * argv[])
           {9, {{3, 2}, {7, 6}}}
       }
   );
+  std::cout << "\nChecking weight traversing graph from node 1 using DFS...\n";
+  InfoDFS resultDFS = graphMST.DFS(graphMST.GetNodeCopy(1));
+  std::cout << "DFS total weight traversed: " << resultDFS.totalWeight << std::endl;
+
+  std::cout << "\nChecking weight traversing graph from node 1 using BFS...\n";
+  InfoBFS resultBFS = graphMST.BFS(graphMST.GetNodeCopy(1));
+  std::cout << "BFS total weight traversed: " << resultBFS.totalWeight << std::endl;
+
   InfoMST resultMST = graphMST.KruskalMST();
-  std::cout << "Finding MST using Kruskal's...\n\nMST result: \n";
+  std::cout << "\n\nFinding MST using Kruskal's...\n\nMST result: \n";
   for (const auto &edge : resultMST.edgesMST) {
     std::cout << "Connected nodes: " << edge.second.first << "->"
               << edge.second.second << " with weight of " << edge.first << "\n";
   }
-  std::cout << "Total MST weight: " << resultMST.weightMST << std::endl;
+  std::cout << "Total MST weight: " << resultMST.totalWeight << std::endl;
 }

cpp/algorithms/graphs/weighted/lib-graph.cpp

@@ -14,13 +14,13 @@
 InfoBFS Graph::BFS(const Node& startNode) const
 {
   // Create local object to track the information gathered during traversal
-  InfoBFS searchInfo;
+  InfoBFS bfs;
 
   // Create a queue to visit discovered nodes in FIFO order
   std::queue<const Node *> visitQueue;
 
   // Mark the startNode as in progress until we finish checking adjacent nodes
-  searchInfo[startNode.number].discovered = Gray;
+  bfs.nodeInfo[startNode.number].discovered = Gray;
 
   // Visit the startNode
   visitQueue.push(&startNode);
@@ -31,17 +31,17 @@ InfoBFS Graph::BFS(const Node& startNode) const
     const Node * thisNode = visitQueue.front();
     visitQueue.pop();
     std::cout << "Visiting node " << thisNode->number << std::endl;
-
     // Check if we have already discovered all the adjacentNodes to thisNode
     for (const auto &adjacent : thisNode->adjacent) {
-      if (searchInfo[adjacent.first].discovered == White) {
+      if (bfs.nodeInfo[adjacent.first].discovered == White) {
         std::cout << "Found undiscovered adjacentNode: " << adjacent.first
-                  << "\n";
+                  << " with weight of " << adjacent.second << std::endl;
+        bfs.totalWeight += adjacent.second;
         // Mark the adjacent node as in progress
-        searchInfo[adjacent.first].discovered = Gray;
+        bfs.nodeInfo[adjacent.first].discovered = Gray;
-        searchInfo[adjacent.first].distance =
+        bfs.nodeInfo[adjacent.first].distance =
-            searchInfo[thisNode->number].distance + 1;
+            bfs.nodeInfo[thisNode->number].distance + 1;
-        searchInfo[adjacent.first].predecessor =
+        bfs.nodeInfo[adjacent.first].predecessor =
             &GetNode(thisNode->number);
 
         // Add the discovered node the the visitQueue
@@ -49,11 +49,11 @@ InfoBFS Graph::BFS(const Node& startNode) const
       }
     }
     // We are finished with this node and the adjacent nodes; Mark it discovered
-    searchInfo[thisNode->number].discovered = Black;
+    bfs.nodeInfo[thisNode->number].discovered = Black;
   }
 
   // Return the information gathered from this search, JIC caller needs it
-  return searchInfo;
+  return bfs;
 }
 
 std::deque<Node> Graph::PathBFS(const Node &start, const Node &finish) const
@@ -62,8 +62,8 @@ std::deque<Node> Graph::PathBFS(const Node &start, const Node &finish) const
   // + If the caller modifies these, it will not impact the graph's data
   std::deque<Node> path;
 
-  InfoBFS searchInfo = BFS(start);
+  InfoBFS bfs = BFS(start);
-  const Node * next = searchInfo[finish.number].predecessor;
+  const Node * next = bfs.nodeInfo[finish.number].predecessor;
   bool isValid = false;
   do {
     // If we have reached the start node, we have found a valid path
@@ -74,7 +74,7 @@ std::deque<Node> Graph::PathBFS(const Node &start, const Node &finish) const
     path.emplace_front(*next);
 
     // Move to the next node
-    next = searchInfo[next->number].predecessor;
+    next = bfs.nodeInfo[next->number].predecessor;
   } while (next != nullptr);
   // Use emplace_back to call Node copy constructor
   path.emplace_back(finish);
@@ -89,85 +89,83 @@ std::deque<Node> Graph::PathBFS(const Node &start, const Node &finish) const
 InfoDFS Graph::DFS() const
 {
   // Track the nodes we have discovered
-  InfoDFS searchInfo;
+  InfoDFS dfs;
   int time = 0;
 
   // Visit each node in the graph
   for (const auto & node : nodes_) {
     std::cout << "Visiting node " << node.number << std::endl;
     // If the node is undiscovered, visit it
-    if (searchInfo[node.number].discovered == White) {
+    if (dfs.nodeInfo[node.number].discovered == White) {
       std::cout << "Found undiscovered node: " << node.number << std::endl;
       // Visiting the undiscovered node will check it's adjacent nodes
-      DFSVisit(time, node, searchInfo);
+      DFSVisit(time, node, dfs);
     }
   }
 
-  return searchInfo;
+  return dfs;
 }
 
 InfoDFS Graph::DFS(const Node &startNode) const
 {
   // Track the nodes we have discovered
-  InfoDFS searchInfo;
+  InfoDFS dfs;
   int time = 0;
 
-  auto startIter = std::find(nodes_.begin(), nodes_.end(),
+  auto startIter =
-                             Node(startNode.number, {})
+      std::find(nodes_.begin(), nodes_.end(), Node(startNode.number, { }));
-  );
-
   // beginning at startNode, visit each node in the graph until we reach the end
   while (startIter != nodes_.end()) {
     std::cout << "Visiting node " << startIter->number << std::endl;
     // If the startIter is undiscovered, visit it
-    if (searchInfo[startIter->number].discovered == White) {
+    if (dfs.nodeInfo[startIter->number].discovered == White) {
-      std::cout << "Found undiscovered node: " << startIter->number << std::endl;
+      std::cout << "Found undiscovered node: " << startIter->number
+                << std::endl;
       // Visiting the undiscovered node will check it's adjacent nodes
-      DFSVisit(time, *startIter, searchInfo);
+      DFSVisit(time, *startIter, dfs);
     }
     startIter++;
   }
 
   // Once we reach the last node, check the beginning for unchecked nodes
   startIter = nodes_.begin();
-
   // Once we reach the initial startNode, we have checked all nodes
   while (*startIter != startNode) {
     std::cout << "Visiting node " << startIter->number << std::endl;
     // If the startIter is undiscovered, visit it
-    if (searchInfo[startIter->number].discovered == White) {
+    if (dfs.nodeInfo[startIter->number].discovered == White) {
       std::cout << "Found undiscovered node: " << startIter->number << std::endl;
       // Visiting the undiscovered node will check it's adjacent nodes
-      DFSVisit(time, *startIter, searchInfo);
+      DFSVisit(time, *startIter, dfs);
     }
     startIter++;
   }
 
-  return searchInfo;
+  return dfs;
 }
 
-void Graph::DFSVisit(int &time, const Node& startNode, InfoDFS &searchInfo) const
+void Graph::DFSVisit(int &time, const Node& startNode, InfoDFS &dfs) const
 {
-  searchInfo[startNode.number].discovered = Gray;
+  dfs.nodeInfo[startNode.number].discovered = Gray;
   time++;
-  searchInfo[startNode.number].discoveryFinish.first = time;
+  dfs.nodeInfo[startNode.number].discoveryFinish.first = time;
 
   // Check the adjacent nodes of the startNode
   for (const auto & adjacent : startNode.adjacent) {
-    auto iter = std::find(nodes_.begin(), nodes_.end(),
+    const auto node = GetNode(adjacent.first);
-                          Node(adjacent.first, {}));
     // If the adjacentNode is undiscovered, visit it
     // + Offset by 1 to account for 0 index of discovered vector
-    if (searchInfo[iter->number].discovered == White) {
+    if (dfs.nodeInfo[node.number].discovered == White) {
-      std::cout << "Found undiscovered adjacentNode: "
+      std::cout << "Found undiscovered adjacentNode: " << adjacent.first
-                << GetNode(adjacent.first).number << std::endl;
+                << " with weight of " << adjacent.second << std::endl;
       // Visiting the undiscovered node will check it's adjacent nodes
-      DFSVisit(time, *iter, searchInfo);
+      dfs.totalWeight += adjacent.second;
+      DFSVisit(time, node, dfs);
     }
   }
-  searchInfo[startNode.number].discovered = Black;
+  dfs.nodeInfo[startNode.number].discovered = Black;
   time++;
-  searchInfo[startNode.number].discoveryFinish.second = time;
+  dfs.nodeInfo[startNode.number].discoveryFinish.second = time;
 }
 
 std::vector<Node> Graph::TopologicalSort(const Node &startNode) const
@@ -177,8 +175,8 @@ std::vector<Node> Graph::TopologicalSort(const Node &startNode) const
   std::vector<Node> order(nodes_);
 
   auto comp = [&topological](const Node &a, const Node &b) {
-    return (topological[a.number].discoveryFinish.second <
+    return (topological.nodeInfo[a.number].discoveryFinish.second <
-      topological[b.number].discoveryFinish.second);
+            topological.nodeInfo[b.number].discoveryFinish.second);
   };
 
   std::sort(order.begin(), order.end(), comp);
@@ -190,26 +188,26 @@ std::vector<Node> Graph::TopologicalSort(const Node &startNode) const
 
 InfoMST Graph::KruskalMST() const
 {
-  InfoMST searchInfo(nodes_);
+  InfoMST mst(nodes_);
   // The ctor for InfoMST initializes all edges within the graph into a multimap
   // + Key for multimap is edge weight, so they're already sorted in ascending
 
   // For each edge in the graph, check if they are part of the same tree
   // + Since we do not want to create a cycle in the MST forest -
   // + we don't connect nodes that are part of the same tree
-  for (const auto &edge : searchInfo.edges) {
+  for (const auto &edge : mst.edges) {
     // Two integers representing the node.number for the connected nodes
     const int u = edge.second.first;
     const int v = edge.second.second;
     // Check if the nodes are of the same tree
-    if (searchInfo.FindSet(u) != searchInfo.FindSet(v)) {
+    if (mst.FindSet(u) != mst.FindSet(v)) {
       // If they are not, add the edge to our MST
-      searchInfo.edgesMST.emplace(edge);
+      mst.edgesMST.emplace(edge);
-      searchInfo.weightMST += edge.first;
+      mst.totalWeight += edge.first;
       // Update the forest to reflect this change
-      searchInfo.Union(u, v);
+      mst.Union(u, v);
     }
   }
 
-  return searchInfo;
+  return mst;
 }

cpp/algorithms/graphs/weighted/lib-graph.hpp

@@ -69,18 +69,29 @@ enum Color {
   Black
 };
 
-// Information used in all searches
+// Information used in all searches tracked for each node
-struct SearchInfo {
+struct NodeInfo {
   // Coloring of the nodes is used in both DFS and BFS
   Color discovered = White;
 };
 
+// Template for tracking graph information gathered during traversals
+// + Used for DFS, BFS, and MST
+template <typename T>
+struct GraphInfo {
+  // Store search information in unordered_maps so we can pass it around easily
+  // + Allows each node to store relative information on the traversal
+  std::unordered_map<int, T> nodeInfo;
+  // Track total weight for all traversals
+  int totalWeight = 0;
+};
+
 
 /******************************************************************************/
 // BFS search information struct
 
-// Information that is only used in BFS
+// Node search information that is only used in BFS
-struct BFS : SearchInfo {
+struct BFS : NodeInfo {
   // Used to represent distance from start node
   int distance = 0;
   // Used to represent the parent node that discovered this node
@@ -88,16 +99,14 @@ struct BFS : SearchInfo {
   const Node *predecessor = nullptr;
 };
 
-// Store search information in unordered_maps so we can pass it around easily
+struct InfoBFS : GraphInfo<BFS> {/* Members inherited from GraphInfo */};
-// + Allows each node to store relative information on the traversal
-using InfoBFS = std::unordered_map<int, struct BFS>;
 
 
 /******************************************************************************/
 // DFS search information struct
 
 // Information that is only used in DFS
-struct DFS : SearchInfo {
+struct DFS : NodeInfo {
   // Create a pair to track discovery / finish time
   // + Discovery time is the iteration the node is first discovered
   // + Finish time is the iteration the node has been checked completely
@@ -105,18 +114,19 @@ struct DFS : SearchInfo {
   std::pair<int, int> discoveryFinish;
 };
 
+struct InfoDFS : GraphInfo<DFS> {/* Members inherited from GraphInfo */};
+
 
 /******************************************************************************/
 // MST search information struct
 
-struct MST : SearchInfo {
+struct MST : NodeInfo {
   int32_t parent = INT32_MIN;
   int rank = 0;
 };
-using InfoDFS = std::unordered_map<int, struct DFS>;
 
 using Edges = std::multimap<int, std::pair<int, int>>;
-struct InfoMST {
+struct InfoMST : GraphInfo<MST>{
   explicit InfoMST(const std::vector<Node> &nodes)
   {
     for (const auto &node : nodes) {
@@ -134,20 +144,17 @@ struct InfoMST {
     }
   }
 
-  std::unordered_map<int, struct MST> searchInfo;
   // All of the edges within our graph
   // + Since each node stores its own edges, this is initialized in InfoMST ctor
   Edges edges;
 
   // A multimap of the edges found for our MST
   Edges edgesMST;
-  // The total weight of our resulting MST
-  int weightMST = 0;
 
   void MakeSet(int x)
   {
-    searchInfo[x].parent = x;
+    nodeInfo[x].parent = x;
-    searchInfo[x].rank = 0;
+    nodeInfo[x].rank = 0;
   }
 
   void Union(int x, int y)
@@ -157,23 +164,23 @@ struct InfoMST {
 
   void Link(int x, int y)
   {
-    if (searchInfo[x].rank > searchInfo[y].rank) {
+    if (nodeInfo[x].rank > nodeInfo[y].rank) {
-      searchInfo[y].parent = x;
+      nodeInfo[y].parent = x;
     }
     else {
-      searchInfo[x].parent = y;
+      nodeInfo[x].parent = y;
-      if (searchInfo[x].rank == searchInfo[y].rank) {
+      if (nodeInfo[x].rank == nodeInfo[y].rank) {
-        searchInfo[y].rank += 1;
+        nodeInfo[y].rank += 1;
       }
     }
   }
 
   int FindSet(int x)
   {
-    if (x != searchInfo[x].parent) {
+    if (x != nodeInfo[x].parent) {
-      searchInfo[x].parent = FindSet(searchInfo[x].parent);
+      nodeInfo[x].parent = FindSet(nodeInfo[x].parent);
     }
-    return searchInfo[x].parent;
+    return nodeInfo[x].parent;
   }
 };
 
@@ -195,7 +202,7 @@ public:
   // An alternate DFS that checks each node of the graph beginning at startNode
   InfoDFS DFS(const Node &startNode) const;
   // Visit function is used in both versions of DFS
-  void DFSVisit(int &time, const Node& startNode, InfoDFS &searchInfo) const;
+  void DFSVisit(int &time, const Node& startNode, InfoDFS &dfs) const;
   // Topological sort, using DFS
   std::vector<Node> TopologicalSort(const Node &startNode) const;
   // Kruskal's MST