added <algorithm> and <limits> includes

the use of numeric_limits and min_elements requires the inclusion of <algorithm> and <limits>

Chapter04/Search.cpp

@@ -2,6 +2,8 @@
 #include <queue>
 #include <iostream>
 #include <unordered_map>
+#include <algorithm>
+#include <limits>
 
 struct GraphNode
 {