129 lines
4.4 KiB
C++
129 lines
4.4 KiB
C++
/*##############################################################################
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## Author: Shaun Reed ##
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## Legal: All Content (c) 2021 Shaun Reed, all rights reserved ##
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## About: Driver program to test object graph implementation ##
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## ##
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## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
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################################################################################
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*/
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#include "lib-graph.hpp"
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void Graph::BFS(const Node& startNode) const
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{
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// Track the nodes we have discovered
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// TODO: Do this at the end to maintain the state instead of at beginning?
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for (const auto &node : nodes_) node.color = White;
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// Create a queue to visit discovered nodes in FIFO order
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std::queue<Node> visitQueue;
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// Mark the startNode as in progress until we finish checking adjacent nodes
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startNode.color = Gray;
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// Visit the startNode
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visitQueue.push(startNode);
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// Continue to visit nodes until there are none left in the graph
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while (!visitQueue.empty()) {
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// Remove thisNode from the visitQueue, storing its vertex locally
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Node thisNode = visitQueue.front();
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visitQueue.pop();
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std::cout << "Visiting node " << thisNode.number << std::endl;
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// Check if we have already discovered all the adjacentNodes to thisNode
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for (const auto &adjacent : thisNode.adjacent) {
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if (nodes_[adjacent - 1].color == White) {
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std::cout << "Found undiscovered adjacentNode: " << adjacent << "\n";
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// Mark the adjacent node as in progress
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nodes_[adjacent - 1].color = Gray;
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// Add the discovered node the the visitQueue
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visitQueue.push(nodes_[adjacent - 1]);
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}
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}
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// We are finished with this node and the adjacent nodes; Mark it discovered
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thisNode.color = Black;
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}
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}
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void Graph::DFS() const
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{
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// Track the nodes we have discovered
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for (const auto &node : nodes_) node.color = White;
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// Visit each node in the graph
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for (const auto& node : nodes_) {
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std::cout << "Visiting node " << node.number << std::endl;
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// If the node is undiscovered, visit it
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if (node.color == White) {
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std::cout << "Found undiscovered node: " << node.number << std::endl;
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// Visiting the undiscovered node will check it's adjacent nodes
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DFSVisit(node);
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}
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}
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}
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void Graph::DFSVisit(const Node& startNode) const
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{
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startNode.color = Gray;
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// Check the adjacent nodes of the startNode
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for (const auto &adjacent : startNode.adjacent) {
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// If the adjacentNode is undiscovered, visit it
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// + Offset by 1 to account for 0 index of discovered vector
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if (nodes_[adjacent - 1].color == White) {
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std::cout << "Found undiscovered adjacentNode: "
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<< nodes_[adjacent - 1].number << std::endl;
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// Visiting the undiscovered node will check it's adjacent nodes
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DFSVisit(nodes_[adjacent - 1]);
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}
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}
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startNode.color = Black;
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}
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std::vector<Node> Graph::TopologicalSort() const
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{
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std::vector<Node> topologicalOrder;
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// Track the nodes we have discovered
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for (const auto &node : nodes_) node.color = White;
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// Visit each node in the graph
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for (const auto &node : nodes_) {
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std::cout << "Visiting node " << node.number << std::endl;
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// If the node is undiscovered, visit it
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if (node.color == White) {
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std::cout << "Found undiscovered node: " << node.number << std::endl;
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// Visiting the undiscovered node will check it's adjacent nodes
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TopologicalVisit(node, topologicalOrder);
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}
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}
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// The topologicalOrder is read right-to-left in the final result
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// + Output is handled in main as FILO, similar to a stack
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return topologicalOrder;
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}
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void Graph::TopologicalVisit(const Node &startNode,
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std::vector<Node> &order) const
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{
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// Mark the node as visited so we don't visit it twice
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startNode.color = Gray;
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// Check the adjacent nodes of the startNode
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for (const auto& adjacent : startNode.adjacent) {
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// If the adjacentNode is undiscovered, visit it
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if (nodes_[adjacent - 1].color == White) {
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std::cout << "Found undiscovered adjacentNode: " << adjacent << std::endl;
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// Visiting the undiscovered node will check it's adjacent nodes
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TopologicalVisit(nodes_[adjacent - 1], order);
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}
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}
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startNode.color = Black;
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// Add startNode to the topologicalOrder
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order.push_back(startNode);
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}
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