81 lines
2.0 KiB
C++
81 lines
2.0 KiB
C++
#include <cassert>
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#include <functional>
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#include <iostream>
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#include <map>
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#include <regex>
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#include <set>
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#include <string>
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#include <variant>
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using Weight = unsigned;
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using Node = std::string;
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using Edge = std::pair<Node, Node>;
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using Nodes = std::set<Node>;
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using Edges = std::map<Edge, Weight>;
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struct Graph
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{
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void add_edge(std::string const& s)
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{
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static const std::regex re("(.+) to (.+) = (\\d+)");
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std::smatch m;
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if (!std::regex_search(s, m, re)) {
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std::cout << "Failed to match: " << s << "\n";
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abort();
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}
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auto n1 = m.str(1);
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auto n2 = m.str(2);
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auto w = std::stoul(m.str(3));
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auto edge = std::make_pair(n1, n2);
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auto back_edge = std::make_pair(n2, n1);
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nodes_.insert(n1);
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nodes_.insert(n2);
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weights_.insert({edge, w});
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weights_.insert({back_edge, w});
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std::cout << n1 << " <-> " << n2 << " weight: " << w << "\n";
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}
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[[nodiscard]] auto solve_tsp() const -> Weight
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{
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Weight min_weight = ~0U;
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std::vector<Node> nodes(nodes_.begin(), nodes_.end());
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std::sort(nodes.begin(), nodes.end());
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do {
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Weight current_weight = 0;
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std::cout << "\r" << nodes[0];
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for (std::size_t i = 1; i < nodes.size(); ++i) {
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std::cout << " <- " << nodes[i] << std::flush;
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Edge e = std::make_pair(nodes[i - 1], nodes[i]);
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auto it = weights_.find(e);
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assert(it != weights_.end());
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current_weight += it->second;
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}
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std::cout << " " << std::flush;
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if (current_weight < min_weight) {
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min_weight = current_weight;
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std::cout << "\nNew minimum weight: " << min_weight << "\n";
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}
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} while (std::next_permutation(nodes.begin(), nodes.end()));
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std::cout << "\n";
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return min_weight;
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}
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Nodes nodes_;
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Edges weights_;
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};
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auto main() -> int
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{
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Graph g;
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// Parse the input
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for (std::string line; std::getline(std::cin, line);) {
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g.add_edge(line);
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}
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auto w = g.solve_tsp();
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std::cout << "Minimum weight = " << w << "\n";
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return 0;
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} |