Update simple-graph implementation to track discovery and finish time
+ Allows result of topological sort to match examples shown in MIT Algorithms + Correct order of initialization for all graphs and adjacent nodes in graph.cpp + Provide overloaded DFS for beginning at a specific node within the graph
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@@ -1,10 +1,10 @@
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/*#############################################################################
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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 a simple 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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## 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 a simple 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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@@ -13,17 +13,17 @@
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int main (const int argc, const char * argv[])
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{
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// We could initialize the graph with some localNodes...
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std::map<int, std::set<int>> localNodes{
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{1, {2, 5}}, // Node 1
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{2, {1, 6}}, // Node 2
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{3, {4, 6, 7}},
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{4, {3, 7, 8}},
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std::unordered_map<int, std::unordered_set<int>> localNodes{
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{8, {6, 4}},
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{7, {8, 6, 4, 3}},
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{6, {7, 3, 2}},
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{5, {1}},
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{6, {2, 3, 7}},
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{7, {3, 4, 6, 8}},
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{8, {4, 6}},
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{4, {8, 7, 3}},
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{3, {7, 6, 4}},
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{2, {6, 1}}, // Node 2...
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{1, {5, 2}}, // Node 1
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};
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// Graph bfsGraph(localNodes);
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Graph exampleGraph(localNodes);
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std::cout << "\n\n##### Breadth First Search #####\n";
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@@ -31,14 +31,14 @@ int main (const int argc, const char * argv[])
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// Initialize a example graph for Breadth First Search
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Graph bfsGraph (
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{
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{1, {2, 5}}, // Node 1
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{2, {1, 6}}, // Node 2...
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{3, {4, 6, 7}},
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{4, {3, 7, 8}},
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{8, {6, 4}},
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{7, {8, 6, 4, 3}},
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{6, {7, 3, 2}},
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{5, {1}},
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{6, {2, 3, 7}},
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{7, {3, 4, 6, 8}},
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{8, {4, 6}},
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{4, {8, 7, 3}},
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{3, {7, 6, 4}},
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{2, {6, 1}}, // Node 2...
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{1, {5, 2}}, // Node 1
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}
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);
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// The graph traversed in this example is seen in MIT Intro to Algorithms
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@@ -50,12 +50,12 @@ int main (const int argc, const char * argv[])
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// Initialize an example graph for Depth First Search
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Graph dfsGraph (
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{
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{1, {2, 4}},
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{2, {5}},
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{3, {5, 6}},
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{4, {2}},
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{5, {4}},
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{6, {6}},
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{5, {4}},
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{4, {2}},
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{3, {6, 5}},
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{2, {5}},
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{1, {4, 2}},
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}
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);
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// The graph traversed in this example is seen in MIT Intro to Algorithms
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@@ -67,32 +67,62 @@ int main (const int argc, const char * argv[])
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// Initialize an example graph for Topological Sort
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Graph topologicalGraph (
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{
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{1, {4, 5}},
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{2, {5}},
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{3, {}},
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{4, {5, 7}},
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{5, {}},
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{6, {7, 8}},
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{7, {9}},
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{8, {9}},
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{9, {}},
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{8, {9}},
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{7, {9}},
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{6, {7, 8}},
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{5, {}},
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{4, {7, 5}},
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{3, {}},
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{2, {5}},
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{1, {5, 4}},
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}
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);
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auto order = topologicalGraph.TopologicalSort(topologicalGraph.GetNode(6));
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std::cout << "\nTopological order: ";
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while (!order.empty()) {
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std::cout << order.back() << " ";
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order.pop_back();
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}
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std::cout << std::endl << std::endl;
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// If we want the topological order to match what is seen in the book
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// + We have to initialize the graph carefully to get this result -
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// Because this is an unordered_(map/set) initialization is reversed
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// + So the order of nodes on the container below is 6,7,8,9,3,1,4,5,2
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// + The same concept applies to their adjacent nodes (7,8 initializes to 8,7)
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// + In object-graph implementation, I use vectors this does not apply there
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Graph topologicalGraph2 (
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{
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{2, {5}}, // socks
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{5, {}}, // shoes
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{4, {7, 5}}, // pants
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{1, {5, 4}}, // undershorts
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{3, {}}, // watch
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{9, {}}, // jacket
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{7, {9}}, // belt
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{8, {9}}, // tie
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{6, {7, 8}}, // shirt
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}
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);
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// The graph traversed in this example is seen in MIT Intro to Algorithms
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// + Chapter 22, Figure 22.7 on Topological Sort
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// + Each node was replaced with a value from left-to-right, top-to-bottom
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// + Undershorts = 1, Socks = 2, Watch = 3, Pants = 4, etc...
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std::vector<int> order = topologicalGraph.TopologicalSort();
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std::vector<int> order2 =
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topologicalGraph2.TopologicalSort(topologicalGraph2.NodeBegin());
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// Because this is a simple graph with no objects to store finishing time
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// + The result is only one example of valid topological order
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// + There are other valid orders; Final result differs from one in the book
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std::cout << "\n\nTopological order: ";
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while (!order.empty()) {
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std::cout << order.back() << " ";
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order.pop_back();
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std::cout << "\nTopological order: ";
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while (!order2.empty()) {
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std::cout << order2.back() << " ";
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order2.pop_back();
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}
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std::cout << std::endl;
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std::cout << std::endl;
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return 0;
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}
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