Update benchmark

Makefile

@@ -1,6 +1,8 @@
+CXX=g++
+CXXFLAGS=-Wall -Wextra -O3
 
 benchmark: benchmark.cpp
-	g++ -Wall -Wextra -o benchmark benchmark.cpp
+	$(CXX) $(CXXFLAGS) -o benchmark benchmark.cpp
 
 clean:
 	rm -rf benchmark

benchmark.cpp

@@ -1,3 +1,5 @@
+// Initially generated by AI (Google Gemini)
+
 #include <iostream>
 #include <vector>
 #include <string>
@@ -10,7 +12,7 @@
 
 using namespace std::chrono;
 
-typedef std::chrono::time_point<std::chrono::high_resolution_clock> time_p;
+typedef time_point<high_resolution_clock> time_p;
 
 // Configuration
 const int NUM_ELEMENTS = 1000000;