diff --git a/2022/city/10/domino/main.cpp b/2022/city/10/domino/main.cpp
new file mode 100644
index 0000000..14c3794
--- /dev/null
+++ b/2022/city/10/domino/main.cpp
@@ -0,0 +1,209 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+// ifstream in("test.in");
+// ofstream out("test.out");
+
+
+
+struct Domino {
+    int side1;
+    int side2;
+};
+
+
+// Global variables
+int n;
+int max_length = 1;
+Domino* dominos[28];
+vector<Domino*> dominos_by_side[7];
+unordered_set<Domino*> ignored_dominos;
+
+
+bool evaluate(unordered_set<Domino*>& ignore_candidates) {
+    ignore_candidates.clear();
+
+    // Filled during the loop, used later
+    unordered_set<Domino*> used_dominos;
+
+    // Find degree of each pip
+    int odd_vertices_count = 0;
+    for (int i = 0; i < 7; i++) {
+        int dominos_count = 0;
+        for (auto it = dominos_by_side[i].begin(); it != dominos_by_side[i].end(); it++) {
+            if (ignored_dominos.count(*it) != 1) {
+                dominos_count++;
+                used_dominos.insert(*it);
+            }
+        }
+
+        // Mark as ignored candidate all dominos with pips that have odd degree
+        if (dominos_count % 2 == 1) {
+            odd_vertices_count++;
+            ignore_candidates.insert(dominos_by_side[i].begin(), dominos_by_side[i].end());
+        }
+    }
+    // cout << odd_vertices_count << " odd vertices found" << endl;
+
+    // Condition 1
+    if (odd_vertices_count > 2) {
+        return false;
+    }
+    
+    // Now evaluate using DFS here
+    // cout << "Evaluating with DFS" << endl;
+    unordered_set<Domino*> visited_dominos;
+    visited_dominos.clear();
+    deque<Domino*> domino_queue;
+    domino_queue.push_back(*used_dominos.begin());
+    visited_dominos.insert(*used_dominos.begin());
+    bool visited_pips[7];
+    for (int i = 0; i < 7; i++) {
+        visited_pips[i] = 0;
+    }
+
+    while (domino_queue.size() > 0) {
+        Domino* domino = domino_queue.front();
+        domino_queue.pop_front();
+
+        if (!visited_pips[domino->side1]) {
+            for (auto it = dominos_by_side[domino->side1].begin(); it != dominos_by_side[domino->side1].end(); it++) {
+                if (ignored_dominos.count(*it) == 1) {
+                    continue;
+                }
+                if (visited_dominos.count(*it) == 0) {
+                    visited_dominos.insert(*it);
+                    domino_queue.push_back(*it);
+                }
+            }
+            visited_pips[domino->side1] = 1;
+        }
+
+        if (!visited_pips[domino->side2]) {
+            for (auto it = dominos_by_side[domino->side2].begin(); it != dominos_by_side[domino->side2].end(); it++) {
+                if (ignored_dominos.count(*it) == 1) {
+                    continue;
+                }
+                if (visited_dominos.count(*it) == 0) {
+                    visited_dominos.insert(*it);
+                    domino_queue.push_back(*it);
+                }
+            }
+            visited_pips[domino->side2] = 1;
+        }
+    }
+
+    if (visited_dominos.size() != used_dominos.size()) {
+        cout << "DFS invalid " << visited_dominos.size() << "/" << used_dominos.size() << " visited" << endl;
+        // ignore_candidates.insert(used_dominos.begin(), used_dominos.end());
+        if (visited_dominos.size() > (used_dominos.size() / 2)) {
+            for (auto it = used_dominos.begin(); it != used_dominos.end(); it++) {
+                if (visited_dominos.count(*it) == 0) {
+                    ignore_candidates.insert(*it);
+                }
+            }
+        } else {
+            ignore_candidates.insert(used_dominos.begin(), used_dominos.end());
+        }
+        return false;
+    }
+    // cout << "DFS VALID" << endl;
+    return true;
+}
+
+
+bool evaluate() {
+    unordered_set<Domino*> empty_set;
+    return evaluate(empty_set);
+}
+
+
+
+
+void solve() {
+    // cout << ignored_dominos.size() << " ignored dominos deep" << endl;
+
+    unordered_set<Domino*> ignore_candidates;  // populated in evaluate()
+    if (evaluate(ignore_candidates)) {
+        cout << "Found new max length " << max_length << endl;
+        max_length = max(max_length, (int)(n - ignored_dominos.size()));
+        return;
+    }
+
+    // Evaluate if it's worth going deeper based on previous findings
+    if (max_length > (n - ignored_dominos.size() - 1)) {
+        return;
+    }
+
+    // for (int i = 0; i < dominos_to_ignore.size(); i++) {
+    for (auto it = ignore_candidates.begin(); it != ignore_candidates.end(); it++) {
+        #define target_domino (*it)
+        if (ignored_dominos.count(target_domino)) {
+            continue;
+        }
+        ignored_dominos.insert(target_domino);
+
+        solve();
+
+        ignored_dominos.erase(target_domino);
+    }
+}
+
+
+
+// pips = vertices; dominos = edges
+// Solve Euler path
+int main(int argc, char *argv[]) {
+    string inName = "test.in";
+    string outName = "test.out";
+    
+    if (argc > 1) {
+        inName = argv[1];
+        cout << "Using \"" << inName << "\" for test name" << endl;
+    } else {
+        cout << "Warning: no in name provided, defaulting to test.in" << endl;
+    }
+
+    if (argc > 2) {
+        outName = argv[2];
+        cout << "Using \"" << outName << "\" for out name" << endl;
+    } else {
+        cout << "Warning: no out name proviced, defaulting to test.out" << endl;
+    }
+
+    ifstream in(inName);
+    ofstream out(outName);
+
+    in >> n;
+
+    // cout << "n: " << n << endl;
+
+    if (n < 2) {
+        out << "1";
+        in.close();
+        out.close();
+        return 0;
+    }
+
+    for (int i = 0; i < n; i++) {
+        Domino* domino = new Domino();
+        in >> (*domino).side1;
+        in >> (*domino).side2;
+
+        dominos[i] = domino;
+
+        dominos_by_side[(domino -> side1)].push_back(domino);
+        dominos_by_side[(domino -> side2)].push_back(domino);
+    }
+
+    ignored_dominos.clear();
+
+    solve();
+    // ignored_dominos.insert(dominos[0]);
+    // cout << dominos[0]->side1 << " " << dominos[0]->side2 << endl;
+    cout << "Result: " << max_length << endl;
+
+    out << max_length << endl;
+    return 0;
+}
diff --git a/2022/city/10/domino/main_slow.cpp b/2022/city/10/domino/main_slow.cpp
new file mode 100644
index 0000000..574e972
--- /dev/null
+++ b/2022/city/10/domino/main_slow.cpp
@@ -0,0 +1,143 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+// ifstream in("test.in");
+// ofstream out("test.out");
+
+
+struct Domino {
+    int side1;
+    int side2;
+};
+
+
+// Global variables
+int n;
+int max_length = 1;
+unordered_set<Domino*> used_dominos;
+vector<Domino*> dominos_by_side[7]; 
+
+
+// Recursive solution
+void buildTrain(int next_side, int current_length) {
+    // cout << "Building train; Current length: " << current_length << "; next side: " << next_side << endl;
+    if (current_length > max_length) {
+        max_length = current_length;
+
+        // Debug print
+        // cout << "updated to " << current_length << endl;
+        // if (max_length == 8) {
+        //     cout << "found 8" << endl;
+        //     for (auto it = used_dominos.begin(); it != used_dominos.end(); it++) {
+        //         cout << (*it)->side1 << " " << (*it)->side2 << endl;
+        //     }
+        // }
+    }
+    
+    int stop = dominos_by_side[next_side].size();
+    
+    for (int i = 0; i < stop; i++) {
+        // Looking at Domino dominos_by_side[next_side][i]
+        #define matched_domino dominos_by_side[next_side][i]
+        // Skip if already part of the train
+        if (used_dominos.count(matched_domino) > 0) {
+            continue;
+        }
+
+
+        // The logic for elongating the train
+        used_dominos.insert(matched_domino);
+
+        // Figure out if the domino matched by side1 or side2:
+        int other_side;
+        if ((matched_domino->side1) == next_side) {
+            other_side = matched_domino->side2;
+        } else {
+            other_side = matched_domino->side1;
+        }
+
+        // The recursion
+        buildTrain(other_side, current_length + 1);
+
+
+        // Deconstruct
+        used_dominos.erase(matched_domino);
+    }
+}
+
+
+int main(int argc, char *argv[]) {
+
+    string inName = "test.in";
+    string outName = "test.out";
+
+    if (argc > 1) {
+        inName = argv[1];
+        cout << "Using \"" << inName << "\" for test name" << endl;
+    } else {
+        cout << "Warning: no in name provided, defaulting to test.in" << endl;
+    }
+
+    if (argc > 2) {
+        outName = argv[2];
+        cout << "Using \"" << outName << "\" for out name" << endl;
+    } else {
+        cout << "Warning: no out name proviced, defaulting to test.out" << endl;
+    }
+
+    ifstream in(inName);
+    ofstream out(outName);
+
+    in >> n;
+
+    // cout << "n: " << n << endl;
+
+    if (n < 2) {
+        out << "1";
+        in.close();
+        out.close();
+        return 0;
+    }
+    
+
+    Domino* dominos[n];
+    for (int i = 0; i < n; i++) {
+        Domino* domino = new Domino();
+        in >> (*domino).side1;
+        in >> (*domino).side2;
+
+        dominos[i] = domino;
+
+        dominos_by_side[(domino -> side1)].push_back(domino);
+        dominos_by_side[(domino -> side2)].push_back(domino);
+    }
+
+    // Debug print
+    for (int j = 0; j < n; j++) {
+        cout << dominos[j] << endl;
+        cout << (dominos[j]->side1) << " " << (dominos[j]->side2) << endl;
+    } 
+
+    used_dominos.clear();
+    // for (int i = 0; i < n; i++) {
+    //     #define start_domino dominos[i]
+
+    //     // cout << "starting with domino " << start_domino->side1 << " " << start_domino->side2 <<  "" << start_domino << endl;
+    //     used_dominos.insert(start_domino);
+
+    //     buildTrain(start_domino->side1, 1);
+    //     buildTrain(start_domino->side2, 1);
+
+    //     used_dominos.clear();
+    // }
+
+    used_dominos.insert(dominos[2]);
+    cout << "start " << dominos[2]->side1 << " " << dominos[2]->side2 << endl;
+    buildTrain(dominos[2]->side1, 1); 
+
+
+    cout << "Result: " << max_length << endl;
+
+    return 0;
+}