+ // Merge the moves, with deduplication.
+ unordered_set<string> moves;
+ for (int i = 0; i < c0.move_size(); ++i) {
+ moves.insert(c0.move(i));
+ c.add_move(c0.move(i));
+ }
+ for (int i = 0; i < c1.move_size(); ++i) {
+ if (!moves.count(c1.move(i))) {
+ c.add_move(c1.move(i));
+ }
+ }
+