Minimum Depth of a Binary Tree

BinaryTreeMinDepth.java

/**
 * Created by suhas on 21/03/17.
 */

class BinaryTree<T> {
    class Node<T> {
        T val;
        BinaryTree left;
        BinaryTree right;
        Node(T val, BinaryTree left, BinaryTree right) {
            this.val = val;
            this.left = left;
            this.right = right;
        }
    }

    Node root;

    BinaryTree(T val) {
        this.root = new Node(val, null, null);
    }

    int minDepth(BinaryTree tree) {
        if (tree == null) {
            return 0;
        }
        else if (tree.root.left == null && tree.root.right == null) {
            return 1;
        }
        else if (tree.root.right == null) {
            return minDepth(tree.root.left) + 1;
        }
        else if (tree.root.left == null) {
            return minDepth(tree.root.right) + 1;
        }
        return Math.min(minDepth(tree.root.left), minDepth(tree.root.right)) + 1;
    }
}


public class BinaryTreeMinDepth {

    public static void  main(String[] args) {
        BinaryTree tree = new BinaryTree(1);
        tree.root.left = new BinaryTree(2);
        tree.root.left.root.left = new BinaryTree(4);
        tree.root.left.root.right = new BinaryTree(5);
        tree.root.right = new BinaryTree(3);
        tree.root.right.root.right = new BinaryTree(7);
        tree.root.right.root.right.root.left = new BinaryTree(6);

        System.out.println(tree.minDepth(tree));
    }
}