A c++ implementation of the A* search algorithm using a priority queue and a templated weight-type. The algorithm finds the shortest path between two nodes on a weighted graph.
A node uses a templated cost_type and contains a vector of edges and two cost_type values: tentative and heuristic. An edge is a pair of node* and cost_type. The path method takes two node& and returns a cost_type of the sum of the weighs of all of the edges along the shortest possible path between the two nodes. If a path does not exist, std::numeric_limits<cost_type>::max() is returned. If a path was found, the tentative values of all of the nodes along the path are equal to the sum of the weights of all the edges along the shortest possible path from the start node to the node. This means you can retrace the shortest path by starting at the goal node and following the nodes with the smallest tentative values until you reach the start node. Minimal code example below.
#include <iostream>
#include "astar.hpp"
int main(){
astar::node<unsigned> n0, n1; // Two nodes.
n0.edges.emplace_back(&n1, 1u); // Add a path with a cost of 1 from n0 to n1.
std::cout << astar::path(n0, n1) << std::endl; // The shortest path from n0 to n1 should be 1.
std::cout << n0.tentative << ", " << n1.tentative << std::endl; // The tentative values should be 0, and 1.
}