Solution for http://www.geeksforgeeks.org/deepest-left-leaf-node-in-a-binary-tree/

DeepestNode.java

public class DeepestDepth {

	static DeepestDepth ts = new DeepestDepth();
	static Node maxNode;
	static int maxDepth = 0;

	public static void main(String[] args) {
		Node l1221 = ts.new Node(null, null, 8);
		Node l122 = ts.new Node(null, l1221, 4);
		Node l121 = ts.new Node(null, null, 7);
		Node r12 = ts.new Node(null, null, 4);
		Node l12 = ts.new Node(l122, l121, 5);
		Node l11 = ts.new Node(null, null, 2);
		Node r1 = ts.new Node(r12, null, 5);
		Node l1 = ts.new Node(l12, l11, 3);
		Node root = ts.new Node(r1, l1, 6);
		deepestDepth(root);
		System.out.println(maxNode.value);
	}

	public static void deepestDepth(Node root) {
		dfs(root, 1);
	}

	public static void dfs(Node node, int depth) {
		if (node == null)
			return;
		if (depth > maxDepth) {
			maxDepth = depth;
			maxNode = node;
		}
		depth++;
		dfs(node.right, depth);
		dfs(node.left, depth);
	}

	class Node {

		Node right;
		Node left;
		int value;

		public Node(Node right, Node left, int value) {
			this.right = right;
			this.left = left;
			this.value = value;
		}

	}

}