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Ayush Karn
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Added Avl tree, BFS, DFS, Egg Drop problem, Kadane Algo, LCS
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‎classical_algorithms/java/AVL_Tree.java

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/*
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Copyright 2020 Sakshi Khachane
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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public class AVL_Tree
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{
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//Declaring Node class
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private class Node
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{
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int data;
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Node left;
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Node right;
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int height;
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public Node(int data)
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{
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this.data = data;
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this.height = 1;
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}
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}
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private Node root;
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public void insert(int num)
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{
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this.root = insert(this.root, num);
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}
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//Display node Function
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public void inOrder(Node node)
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{
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if (node != null)
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{
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inOrder(node.left);
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System.out.print(node.data + " ");
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inOrder(node.right);
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}
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}
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//preorder traversal
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public void preOrder(Node node)
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{
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if (node != null)
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{
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System.out.print(node.data + " ");
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preOrder(node.left);
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preOrder(node.right);
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}
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}
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//post order traversal
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public void postOrder(Node node)
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{
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if (node != null)
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{
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postOrder(node.left);
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postOrder(node.right);
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System.out.print(node.data + " ");
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}
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}
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private Node insert(Node node1, int num)
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{
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if (node1 == null)
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{
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Node node2 = new Node(num);
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return node2;
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}
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if (num > node1.data)
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{
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node1.right = insert(node1.right, num);
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} else if (num < node1.data)
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{
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node1.left = insert(node1.left, num);
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}
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node1.height = Math.max(height(node1.left), height(node1.right)) + 1;
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int balancefac = balancefac(node1);
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// L-L Case
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if (balancefac > 1 && num < node1.left.data)
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{
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return rightRotate(node1);
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}
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// R-R Case
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if (balancefac < -1 && num > node1.right.data)
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{
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return leftRotate(node1);
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}
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// L-R Case
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if (balancefac > 1 && num > node1.left.data)
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{
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node1.left = leftRotate(node1.left);
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return rightRotate(node1);
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}
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// R-L Case
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if (balancefac < -1 && num < node1.right.data)
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{
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node1.right = rightRotate(node1.right);
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return leftRotate(node1);
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}
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return node1;
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}
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//Finding height of the node
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private int height(Node num)
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{
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if (num == null)
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{
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return 0;
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}
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return num.height;
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}
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//Balance Factor
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private int balancefac(Node num)
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{
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if (num == null)
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{
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return 0;
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}
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return height(num.left) - height(num.right);
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}
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//performing right rotation
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private Node rightRotate(Node node3)
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{
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Node node4 = node3.left;
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Node node = node4.right;
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node4.right = node3;
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node3.left = node;
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node3.height = Math.max(height(node3.left), height(node3.right)) + 1;
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node4.height = Math.max(height(node4.left), height(node4.right)) + 1;
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return node4;
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}
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//performing left rotation
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private Node leftRotate(Node node3)
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{
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Node node4 = node3.right;
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Node node = node4.left;
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node4.left = node3;
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node3.right = node;
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node3.height = Math.max(height(node3.left), height(node3.right)) + 1;
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node4.height = Math.max(height(node4.left), height(node4.right)) + 1;
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return node4;
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}
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public static void main(String[] args)
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{
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AVL_Tree tree = new AVL_Tree();
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tree.insert(10);
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tree.insert(20);
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tree.insert(30);
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tree.insert(40);
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tree.insert(50);
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tree.insert(25);
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System.out.println("Preorder display: ");
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tree.preOrder(tree.root);
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System.out.println("\n\nInorder display: ");
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tree.inOrder(tree.root);
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System.out.println("\n\nPostorder display: ");
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tree.postOrder(tree.root);
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}
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}
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/* Input:
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* 10 20 30 40 50 25
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*/
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/*
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* Output:
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*
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* Preorder display:
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30 20 10 25 40 50
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Inorder display:
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10 20 25 30 40 50
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Postorder display:
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10 25 20 50 40 30
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*/

‎classical_algorithms/java/BreadthFirstTraversal.java

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/*
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Copyright 2017 Aman Mehara
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import java.util.HashSet;
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import java.util.PriorityQueue;
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import java.util.Queue;
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import java.util.Set;
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public class BreadthFirstTraversal<V> {
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public void breadthFirstTraversal(DirectedGraph<V> graph, V vertex) {
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final Set<V> visited = new HashSet<>();
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final Queue<V> queue = new PriorityQueue<>();
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queue.add(vertex);
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visited.add(vertex);
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while (!queue.isEmpty()) {
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V s = queue.remove();
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graph.adjacencyList().get(s).forEach(v -> {
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if (!visited.contains(v)) {
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visited.add(v);
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queue.add(v);
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}
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});
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}
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}
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}

‎classical_algorithms/java/DepthFirstTraversal.java

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/*
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Copyright 2017 Aman Mehara
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import java.util.*;
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public class DepthFirstTraversal<V> {
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public void depthFirstTraversal(DirectedGraph<V> graph, V vertex) {
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final Set<V> visited = new HashSet<>();
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recurse(graph, vertex, visited);
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}
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private void recurse(DirectedGraph<V> graph, V vertex, Set<V> visited) {
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visited.add(vertex);
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graph.adjacencyList().get(vertex).forEach(v -> {
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if (!visited.contains(v)) {
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recurse(graph, v, visited);
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}
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});
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}
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}

‎classical_algorithms/java/Egg_Drop.java

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import java.util.*;
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import java.io.*;
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public class Egg_Drop {
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static int eggDrop(int n,int k)
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{
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// boundary condition
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// if 1 egg and k floors, min attempt = k
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// if n eggs and 1 floor, min attempt =1
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int T[][]=new int[n][k+1];
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for (int i = 0; i <=k; i++) {
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T[0][i]=i;
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}
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for (int i = 0; i < n; i++) {
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T[i][0]=0;
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T[i][1]=1;
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}
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for (int i = 1; i < n; i++) {
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for (int j = 2; j <=k; j++) {
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T[i][j]=999;
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for(int x=1;x<=j;x++)
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{
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int res=1+Math.max(T[i-1][x-1],T[i][j-x]);
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if(res<T[i][j])
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{
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T[i][j]=res;
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}
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}
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}
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}
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for (int i = 0; i < n; i++) {
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for (int j = 0; j <=k; j++) {
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System.out.print(T[i][j]+" ");
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}
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System.out.println("");
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}
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return (T[n-1][k]);
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}
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public static void main(String[] args) {
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int N=2; //eggs
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int K=4;
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System.out.println("Minimum Attempts: "+eggDrop(N,K));
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}
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}

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