add test in main method

main.cpp

@@ -1,5 +1,14 @@
+#include <cstdlib>
+#include <iostream>
+#include <cassert>
 
+#include "areas.h"
 
 int main() {
+    srand(987192345);
+    std::vector<Rectangle> inst1 = get_random_instance(10,100);
+    Unit area = get_area_union(inst1);
+    std::cout << "Area is " << area << "." << std::endl;
+    assert(area == 6559);
     return 0;
 }

segment_tree.cpp

@@ -1,7 +1,7 @@
 //
 // Created by maximilian on 16.04.22.
 //
-#include <assert.h>
+#include <cassert>
 #include <bit>
 #include "segment_tree.h"