66 lines
2.4 KiB
C++
66 lines
2.4 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: An example of a simple graph implementation ##
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## Algorithms in this example are found in MIT Intro to Algorithms ##
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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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#ifndef LIB_GRAPH_HPP
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#define LIB_GRAPH_HPP
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#include <iostream>
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#include <queue>
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#include <vector>
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#include <unordered_map>
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#include <unordered_set>
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class Graph {
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public:
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using Node = std::unordered_map<int, std::unordered_set<int>>;
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explicit Graph(Node nodes) : nodes_(std::move(nodes))
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{
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discoveryTime.resize(nodes_.size());
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finishTime.resize(nodes_.size(), std::make_pair(0,0));
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predecessor.resize(nodes_.size(), std::make_pair(0, INT32_MIN));
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distance.resize(nodes_.size(), std::make_pair(0, 0));
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}
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void BFS(int startNode);
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std::deque<int> PathBFS(int start, int finish);
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void DFS();
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void DFS(Node::iterator startNode);
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void DFSVisit(int &time, int startNode, std::vector<bool> &discovered);
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std::vector<int> TopologicalSort(Node::iterator startNode);
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void TopologicalVisit(
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int startNode, std::vector<bool> &discovered, std::vector<int> &order
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);
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// Define a comparator for std::sort
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// + This will help to sort nodes by finished time after traversal
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static bool FinishedSort(std::pair<int, int> &node1, decltype(node1) &node2)
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{ return node1.second < node2.second;}
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inline Node::iterator NodeBegin() { return nodes_.begin();}
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// A non-const accessor for direct access to a node with the number value i
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inline Node::iterator GetNode(int i) { return nodes_.find(i);}
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private:
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// Unordered to avoid container reorganizing elements
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// + Since this would alter the order nodes are traversed in
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Node nodes_;
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std::vector<std::pair<int, int>> distance;
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std::vector<std::pair<int, int>> predecessor;
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// Where the first element in the following two pairs is the node number
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// And the second element is the discovery / finish time
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std::vector<std::pair<int, int>> discoveryTime;
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std::vector<std::pair<int, int>> finishTime;
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};
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#endif // LIB_GRAPH_HPP
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