Merge pull request TheAlgorithms#185 from varunu28/master

Create FindHeightOfTree.java

Author: varunu28

data_structures/Trees/FindHeightOfTree.java

@@ -0,0 +1,100 @@
+/**
+ *
+ * @author Varun Upadhyay (https://github.com/varunu28)
+ *
+ */
+import java.util.LinkedList;
+
+public class FindHeightOfTree {
+
+    // Driver Program
+    public static void main(String[] args) {
+        Node tree = new Node(5);
+        tree.insert(3);
+        tree.insert(7);
+        tree.insert(1);
+        tree.insert(-1);
+        tree.insert(29);
+        tree.insert(93);
+        tree.insert(6);
+        tree.insert(0);
+        tree.insert(-5);
+        tree.insert(-6);
+        tree.insert(-8);
+        tree.insert(-1);
+
+        // A level order representation of the tree
+        tree.printLevelOrder();
+        System.out.println();
+
+        System.out.println("Height of the tree is: " + tree.findHeight());
+    }
+}
+
+/**
+ * The Node class which initializes a Node of a tree
+ * printLevelOrder: ROOT -> ROOT's CHILDREN -> ROOT's CHILDREN's CHILDREN -> etc
+ * findHeight: Returns the height of the tree i.e. the number of links between root and farthest leaf
+ */
+class Node {
+    Node left, right;
+    int data;
+
+    public Node(int data) {
+        this.data = data;
+    }
+
+    public void insert (int value) {
+        if (value < data) {
+            if (left == null) {
+                left = new Node(value);
+            }
+            else {
+                left.insert(value);
+            }
+        }
+        else {
+            if (right == null) {
+                right = new Node(value);
+            }
+            else {
+                right.insert(value);
+            }
+        }
+    }
+
+    public void printLevelOrder() {
+        LinkedList<Node> queue = new LinkedList<>();
+        queue.add(this);
+        while(!queue.isEmpty()) {
+            Node n = queue.poll();
+            System.out.print(n.data + " ");
+            if (n.left != null) {
+                queue.add(n.left);
+            }
+            if (n.right != null) {
+                queue.add(n.right);
+            }
+        }
+    }
+
+    public int findHeight() {
+        return findHeight(this);
+    }
+
+    private int findHeight(Node root) {
+        if (root.left == null && root.right == null) {
+            return 0;
+        }
+        else if (root.left != null && root.right != null) {
+            return 1 + Math.max(findHeight(root.left), findHeight(root.right));
+        }
+        else if (root.left == null && root.right != null) {
+            return 1 + findHeight(root.right);
+        }
+        else {
+            return 1 + findHeight(root.left);
+        }
+    }
+}
+