Line is represented by line number as key in treap

file.hpp

@@ -4,12 +4,15 @@
 
 using std::string;
 typedef unsigned long long priority_type;
+typedef unsigned long long key_type;
 #define RAND_MAX (1 << 62)
 class line;
 typedef std::pair<line*, line*> two_lines;
 
+// Treap node representation of a line
 class line {
 	priority_type priority;
+	key_type key;
 	string text;
 	line *left, *right;
 
@@ -17,14 +20,30 @@ public:
 	line(priority_type _p, string _t) : priority(_p), text(_t) {}
 
 	two_lines split(string s) { return two_lines(nullptr, nullptr); }
-	void join(line *l) {}
+	void join(line *l) {
+		// Take minimum of priorities of roots
+		// Join subtrees
+	}
 
-	void insert(line *l) {}
-	void remove(string s) {}
-	line* find(string s) { return nullptr; }
+	line* find(key_type k) {
+		if(k < key) {
+			if(left != nullptr)
+				return left->find(k);
+			else
+				return nullptr;
+		}
+		else if(k > key) {
+			if(right != nullptr)
+				return right->find(k);
+			else
+				return nullptr;
+		}
+		else
+			return this;
+	}
 };
 
-// Treap file representation
+// Treap representation of a file
 struct file {
 	line* root;
 
@@ -34,6 +53,12 @@ struct file {
 	}
 	void insert(string s) {
 		line *l = new line(rand(), s);
+
+		if(root == nullptr) {
+			root = l;
+			return;
+		}
+
 		auto two = root->split(s);
 		two.first->join(l);
 		two.first->join(two.second);
@@ -43,7 +68,7 @@ struct file {
 		two.first = two.first->split(s).first; // TODO sharp split
 		two.first->join(two.second);
 	}
-	line* find(string s) {
-		return root->find(s);
+	line* find(key_type k) {
+		return root->find(k);
 	}
 };