Initial commit

2015/puzzle-24-02.cc

@@ -0,0 +1,78 @@
+#include <string>
+#include <vector>
+#include <iostream>
+#include <cstdlib>
+#include <limits>
+#include <algorithm>
+#include <map>
+#include <numeric>
+#include <set>
+
+struct State {
+    std::set<unsigned long> weights_;
+
+    explicit State(unsigned long w) { weights_.insert(w); }
+
+    std::size_t cost() const { return weights_.size(); }
+
+    unsigned long qe() const {
+        return std::accumulate(weights_.begin(), weights_.end(), 1UL,
+                               [](unsigned long l, unsigned long w) { return l * w; });
+    }
+
+    unsigned long weight() const {
+        return std::accumulate(weights_.begin(), weights_.end(), 0UL,
+                               [](unsigned long l, unsigned long w) { return l + w; });
+    }
+
+    bool operator==(State const &rhs) const { return weights_ == rhs.weights_; }
+
+    bool operator<(State const &rhs) const {
+        if (cost() < rhs.cost()) { return true; }
+        if (cost() == rhs.cost()) { return qe() < rhs.qe(); }
+        return false;
+    }
+};
+
+int main() {
+    std::vector<unsigned long> weights;
+    std::string line;
+    while (std::getline(std::cin, line)) {
+        weights.emplace_back(std::stoul(line));
+    }
+
+    std::set<State> states;
+    unsigned long target_weight;
+    for (auto w: weights) {
+        states.insert(State{w});
+        target_weight += w;
+    }
+    target_weight /= 4;
+
+    while (!states.empty()) {
+        auto it = states.begin();
+        State current(*it);
+        states.erase(it);
+
+        if (current.weight() == target_weight) {
+            std::cout << "Cost " << current.cost() << ", qe " << current.qe() << '\n';
+            return 0;
+        }
+        if (current.weight() > target_weight) {
+            continue;
+        }
+
+        for (auto w: weights) {
+            if (current.weights_.find(w) == current.weights_.end()) {
+                auto next{current};
+                next.weights_.insert(w);
+                if (states.find(next) == states.end()) {
+                    states.insert(next);
+                }
+            }
+        }
+    }
+
+    std::cout << "It went wrong somewhere!\n";
+    return 1;
+}