Initial commit

2015/puzzle-13-02.cc

@@ -0,0 +1,86 @@
+#include <cassert>
+#include <cctype>
+#include <climits>
+#include <functional>
+#include <iostream>
+#include <map>
+#include <regex>
+#include <set>
+#include <string>
+#include <variant>
+
+struct Graph {
+  Graph() { nodes_.insert("self"); }
+  using Node = std::string;
+  using Weight = int;
+  using Nodes = std::set<Node>;
+  using NodeList = std::vector<Node>;
+  using Edge = std::pair<Node, Node>;
+  using EdgeWeights = std::map<Edge, Weight>;
+
+  void add_edge(std::string const &s) {
+    static const std::regex re(
+        "(\\w+) would (gain|lose) (\\d+) happiness units? "
+        "by sitting next to (\\w+).");
+    std::smatch m;
+    if (std::regex_search(s, m, re)) {
+      nodes_.insert(m.str(1));
+      weights_.insert({{m.str(1), "self"}, 0});
+      weights_.insert({{"self", m.str(1)}, 0});
+      nodes_.insert(m.str(4));
+      int delta = std::stoi(m.str(3));
+      if (m.str(2) == "lose") {
+        delta = -delta;
+      }
+      weights_.insert({{m.str(1), m.str(4)}, delta});
+    } else {
+      assert(false);
+    }
+  }
+
+  Weight max_happiness() const {
+    int max_happiness = INT_MIN;
+    NodeList nl(nodes_.begin(), nodes_.end());
+    std::sort(nl.begin(), nl.end());
+    do {
+      std::cout << "\r";
+      for (auto const &s : nl) {
+        std::cout << s << " ";
+      }
+      int h = happiness(nl);
+      std::cout << "Happiness = " << h << "       ";
+      if (h > max_happiness) {
+        std::cout << "\n";
+        max_happiness = h;
+      }
+    } while (std::next_permutation(nl.begin(), nl.end()));
+
+    std::cout << "\n";
+    return max_happiness;
+  }
+
+  int happiness(NodeList const &nl) const {
+    int h = 0;
+    h += weights_.find(std::make_pair(nl[nl.size() - 1], nl[0]))->second;
+    h += weights_.find(std::make_pair(nl[0], nl[nl.size() - 1]))->second;
+    for (std::size_t off = 1; off < nl.size(); ++off) {
+      h += weights_.find(std::make_pair(nl[off - 1], nl[off]))->second;
+      h += weights_.find(std::make_pair(nl[off], nl[off - 1]))->second;
+    }
+    return h;
+  }
+
+  Nodes nodes_;
+  EdgeWeights weights_;
+};
+
+int main(int argc, char **argv) {
+  Graph g;
+  for (std::string line; std::getline(std::cin, line);) {
+    g.add_edge(line);
+  }
+
+  auto h = g.max_happiness();
+  std::cout << "Max happiness: " << h << "\n";
+  return 0;
+}