Rename file representation to treap for better readability

treap.hpp

@@ -16,7 +16,7 @@ struct line {
 typedef std::pair<line*, line*> two_lines;
 
 // Treap representation of a file
-class file {
+class treap {
 public:
 	line* root;
 
@@ -79,7 +79,7 @@ public:
 	}
 
 public:
-	file() {
+	treap() {
 		srand(120);
 		root = nullptr;
 	}