Update LCT.mdx

content/6_Advanced/LCT.mdx

@@ -240,6 +240,150 @@ int main() {
 ```
 
 </CPPSection>
+<JavaSection>
+
+```java
+import java.util.*;
+
+class Node {
+	int value;
+	Node left, right, parent;
+	boolean reversed;
+
+	Node(int v) { this.value = v; }
+
+	void push() {
+		if (reversed) {
+			reversed = false;
+			Node temp = left;
+			left = right;
+			right = temp;
+			if (left != null) left.reversed ^= true;
+			if (right != null) right.reversed ^= true;
+		}
+	}
+
+	boolean isRoot() {
+		return parent == null || (parent.left != this && parent.right != this);
+	}
+}
+
+class LCT {
+	Node[] nodes;
+
+	LCT(int n) {
+		nodes = new Node[n + 1];
+		for (int i = 1; i <= n; i++) { nodes[i] = new Node(i); }
+	}
+
+	void rotate(Node child) {
+		Node parent = child.parent;
+		Node grandparent = parent.parent;
+
+		if (!parent.isRoot()) {
+			if (grandparent.right == parent) grandparent.right = child;
+			else grandparent.left = child;
+		}
+
+		parent.push();
+		child.push();
+
+		if (parent.left == child) {
+			parent.left = child.right;
+			if (parent.left != null) parent.left.parent = parent;
+			child.right = parent;
+		} else {
+			parent.right = child.left;
+			if (parent.right != null) parent.right.parent = parent;
+			child.left = parent;
+		}
+
+		parent.parent = child;
+		child.parent = grandparent;
+	}
+
+	void splay(Node node) {
+		while (!node.isRoot()) {
+			Node parent = node.parent;
+			Node grandparent = parent.parent;
+			if (!parent.isRoot()) {
+				rotate((grandparent.right == parent) == (parent.right == node) ? parent
+				                                                               : node);
+			}
+			rotate(node);
+		}
+		node.push();
+	}
+
+	Node access(int v) {
+		Node last = null;
+		Node current = nodes[v];
+		for (Node p = current; p != null; p = p.parent) {
+			splay(p);
+			p.right = last;
+			last = p;
+		}
+		splay(current);
+		return last;
+	}
+
+	void makeRoot(int v) {
+		access(v);
+		Node current = nodes[v];
+		if (current.left != null) {
+			current.left.reversed ^= true;
+			current.left = null;
+		}
+	}
+
+	void link(int u, int v) {
+		makeRoot(v);
+		nodes[v].parent = nodes[u];
+	}
+
+	void cut(int u, int v) {
+		makeRoot(u);
+		access(v);
+		if (nodes[v].left != null) {
+			nodes[v].left.parent = null;
+			nodes[v].left = null;
+		}
+	}
+
+	boolean connected(int u, int v) {
+		makeRoot(u);
+		access(v);
+		return nodes[v].parent != null;
+	}
+}
+
+public class Main {
+	public static void main(String[] args) {
+		Scanner sc = new Scanner(System.in);
+		int n = sc.nextInt();
+		int m = sc.nextInt();
+		LCT lc = new LCT(n);
+
+		for (int i = 0; i < m; i++) {
+			String command = sc.next();
+			int u = sc.nextInt();
+			int v = sc.nextInt();
+
+			if (command.equals("add")) {
+				lc.link(u, v);
+			} else if (command.equals("rem")) {
+				lc.cut(u, v);
+			} else if (command.equals("conn")) {
+				System.out.println(lc.connected(u, v) ? "YES" : "NO");
+			}
+		}
+
+		sc.close();
+	}
+}
+```
+
+</JavaSection>
 </LanguageSection>
 
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