diff -r 27259810da6d -r ee5758ddb6d2 src/basics.h
--- a/src/basics.h	Sat Jun 11 14:30:30 2022 +0300
+++ b/src/basics.h	Sat Jun 11 15:20:24 2022 +0300
@@ -20,6 +20,7 @@
 #include <algorithm>
 #include <cmath>
 #include <compare>
+#include <deque>
 #include <memory>
 #include <optional>
 #include <set>
@@ -184,7 +185,7 @@
 struct TypeValue
 {
 	T value;
-	auto operator<=>(TypeValue other) const = default;
+	auto operator<=>(const TypeValue& other) const = default;
 };
 
 template<typename T, typename R>
@@ -323,3 +324,13 @@
 	value += element;
 	return value;
 }
+
+template<typename T>
+struct GraphEdge
+{
+	T from;
+	T to;
+};
+
+template<typename T>
+using Graph = std::deque<GraphEdge<T>>;