diff --git a/graph/dijkstra.cpp b/graph/dijkstra.cpp index 357ecf843..3dca9e64a 100644 --- a/graph/dijkstra.cpp +++ b/graph/dijkstra.cpp @@ -37,31 +37,31 @@ constexpr long long INF = 1000000000; */ namespace graph { - /** - * @brief Function that add edge between two nodes or vertices of graph - * - * @param u any node or vertex of graph - * @param v any node or vertex of graph - */ - void addEdge(std::vector>> *adj, int u, int v, - int w) { +/** + * @brief Function that add edge between two nodes or vertices of graph + * + * @param u any node or vertex of graph + * @param v any node or vertex of graph + */ +void addEdge(std::vector>> *adj, int u, int v, + int w) { (*adj)[u - 1].push_back(std::make_pair(v - 1, w)); // (*adj)[v - 1].push_back(std::make_pair(u - 1, w)); - } - - /** - * @brief Function runs the dijkstra algorithm for some source vertex and - * target vertex in the graph and returns the shortest distance of target - * from the source. - * - * @param adj input graph - * @param s source vertex - * @param t target vertex - * - * @return shortest distance if target is reachable from source else -1 in - * case if target is not reachable from source. - */ - int dijkstra(std::vector>> *adj, int s, int t) { +} + +/** + * @brief Function runs the dijkstra algorithm for some source vertex and + * target vertex in the graph and returns the shortest distance of target + * from the source. + * + * @param adj input graph + * @param s source vertex + * @param t target vertex + * + * @return shortest distance if target is reachable from source else -1 in + * case if target is not reachable from source. + */ +int dijkstra(std::vector>> *adj, int s, int t) { /// n denotes the number of vertices in graph int n = adj->size(); @@ -72,9 +72,9 @@ namespace graph { /// first element of pair contains the distance /// second element of pair contains the vertex std::priority_queue, std::vector>, - std::greater>> + std::greater>> pq; - + /// pushing the source vertex 's' with 0 distance in min heap pq.push(std::make_pair(0, s)); @@ -82,96 +82,97 @@ namespace graph { dist[s] = 0; while (!pq.empty()) { - /// second element of pair denotes the node / vertex - int currentNode = pq.top().second; + /// second element of pair denotes the node / vertex + int currentNode = pq.top().second; - /// first element of pair denotes the distance - int currentDist = pq.top().first; + /// first element of pair denotes the distance + int currentDist = pq.top().first; - pq.pop(); + pq.pop(); - /// for all the reachable vertex from the currently exploring vertex - /// we will try to minimize the distance - for (std::pair edge : (*adj)[currentNode]) { - - /// minimizing distances - if (currentDist + edge.second < dist[edge.first]) { - dist[edge.first] = currentDist + edge.second; - pq.push(std::make_pair(dist[edge.first], edge.first)); + /// for all the reachable vertex from the currently exploring vertex + /// we will try to minimize the distance + for (std::pair edge : (*adj)[currentNode]) { + /// minimizing distances + if (currentDist + edge.second < dist[edge.first]) { + dist[edge.first] = currentDist + edge.second; + pq.push(std::make_pair(dist[edge.first], edge.first)); + } } - } } if (dist[t] != INF) { - return dist[t]; + return dist[t]; } return -1; - } -} // namespace graph +} +} // namespace graph /** Function to test the Algorithm */ void tests() { - std::cout << "Initiatinig Predefined Tests..." << std::endl; - std::cout << "Initiating Test 1..." << std::endl; - std::vector>> adj1(4, std::vector>()); - graph::addEdge(&adj1, 1, 2, 1); - graph::addEdge(&adj1, 4, 1, 2); - graph::addEdge(&adj1, 2, 3, 2); - graph::addEdge(&adj1, 1, 3, 5); + std::cout << "Initiatinig Predefined Tests..." << std::endl; + std::cout << "Initiating Test 1..." << std::endl; + std::vector>> adj1( + 4, std::vector>()); + graph::addEdge(&adj1, 1, 2, 1); + graph::addEdge(&adj1, 4, 1, 2); + graph::addEdge(&adj1, 2, 3, 2); + graph::addEdge(&adj1, 1, 3, 5); - int s = 1, t = 3; - assert(graph::dijkstra(&adj1, s - 1, t - 1) == 3); - std::cout << "Test 1 Passed..." << std::endl; + int s = 1, t = 3; + assert(graph::dijkstra(&adj1, s - 1, t - 1) == 3); + std::cout << "Test 1 Passed..." << std::endl; - s = 4, t = 3; - std::cout << "Initiating Test 2..." << std::endl; - assert(graph::dijkstra(&adj1, s - 1, t - 1) == 5); - std::cout << "Test 2 Passed..." << std::endl; + s = 4, t = 3; + std::cout << "Initiating Test 2..." << std::endl; + assert(graph::dijkstra(&adj1, s - 1, t - 1) == 5); + std::cout << "Test 2 Passed..." << std::endl; - std::vector>> adj2(5, std::vector>()); - graph::addEdge(&adj2, 1, 2, 4); - graph::addEdge(&adj2, 1, 3, 2); - graph::addEdge(&adj2, 2, 3, 2); - graph::addEdge(&adj2, 3, 2, 1); - graph::addEdge(&adj2, 2, 4, 2); - graph::addEdge(&adj2, 3, 5, 4); - graph::addEdge(&adj2, 5, 4, 1); - graph::addEdge(&adj2, 2, 5, 3); - graph::addEdge(&adj2, 3, 4, 4); + std::vector>> adj2( + 5, std::vector>()); + graph::addEdge(&adj2, 1, 2, 4); + graph::addEdge(&adj2, 1, 3, 2); + graph::addEdge(&adj2, 2, 3, 2); + graph::addEdge(&adj2, 3, 2, 1); + graph::addEdge(&adj2, 2, 4, 2); + graph::addEdge(&adj2, 3, 5, 4); + graph::addEdge(&adj2, 5, 4, 1); + graph::addEdge(&adj2, 2, 5, 3); + graph::addEdge(&adj2, 3, 4, 4); - s = 1, t = 5; - std::cout << "Initiating Test 3..." << std::endl; - assert(graph::dijkstra(&adj2, s - 1, t - 1) == 6); - std::cout << "Test 3 Passed..." << std::endl; - std::cout << "All Test Passed..." << std::endl << std::endl; + s = 1, t = 5; + std::cout << "Initiating Test 3..." << std::endl; + assert(graph::dijkstra(&adj2, s - 1, t - 1) == 6); + std::cout << "Test 3 Passed..." << std::endl; + std::cout << "All Test Passed..." << std::endl << std::endl; } /** Main function */ -int main(){ - // running predefined tests - tests(); +int main() { + // running predefined tests + tests(); - int vertices, edges; - std::cout << "Enter the number of vertices : "; - std::cin >> vertices; - std::cout << "Enter the number of edges : "; - std::cin >> edges; + int vertices, edges; + std::cout << "Enter the number of vertices : "; + std::cin >> vertices; + std::cout << "Enter the number of edges : "; + std::cin >> edges; - std::vector>> adj( - vertices, std::vector>()); + std::vector>> adj( + vertices, std::vector>()); - int u, v, w; - while (edges--) { - std::cin >> u >> v >> w; - graph::addEdge(&adj, u, v, w); - } + int u, v, w; + while (edges--) { + std::cin >> u >> v >> w; + graph::addEdge(&adj, u, v, w); + } - int s, t; - std::cin >> s >> t; - int dist = graph::dijkstra(&adj, s-1, t-1); - if (dist == -1) { - std::cout << "Target not reachable from source" << std::endl; - } else { - std::cout << "Shortest Path Distance : " << dist << std::endl; - } - return 0; + int s, t; + std::cin >> s >> t; + int dist = graph::dijkstra(&adj, s - 1, t - 1); + if (dist == -1) { + std::cout << "Target not reachable from source" << std::endl; + } else { + std::cout << "Shortest Path Distance : " << dist << std::endl; + } + return 0; }