public class MyTreeExamples {
	public static void main(String[] args) {
		TreeNode root = new TreeNode(55);
		root.left = new TreeNode(40);
		root.left.left = new TreeNode(21);
		root.left.left.right = new TreeNode(25);
		root.left.right = new TreeNode(44);
		root.left.right.left = new TreeNode(41);
		root.right = new TreeNode(100);
		root.right.left = new TreeNode(60);
		root.right.left.right = new TreeNode(70);
		root.right.right = new TreeNode(120);
		root.right.right.left = new TreeNode(110);
		root.right.right.right = new TreeNode(130);
		System.out.println(getMin(root));
		System.out.println(getMax(root));
		System.out.println(getLastSecondMin(root));
		System.out.println(getLastSecondMax(root));
		System.out.println(getLastSecondMinRecursion(root));
		System.out.println(getLastSecondMaxRecursion(root));
		printInOrder(root);
		System.out.println();
		printPreOrder(root);
		System.out.println();
		printPostOrder(root);
		System.out.println();
		printTree(root);
	}

	public static int getMin(TreeNode root) {
		if (root == null) {
			throw new IllegalArgumentException("No elements");
		}
		TreeNode current = root;
		while (current.left != null) {
			current = current.left;
		}
		return current.value;

	}

	public static int getMax(TreeNode root) {
		if (root == null) {
			throw new IllegalArgumentException("No elements");
		}
		TreeNode current = root;
		while (current.right != null) {
			current = current.right;
		}
		return current.value;
	}

	public static int getLastSecondMin(TreeNode root) {
		if (root == null) {
			throw new IllegalArgumentException("No elements");
		}
		TreeNode min = root;
		int parentMin = 0;
		TreeNode current = root;
		while (min.left != null) {
			parentMin = min.value;
			min = min.left;
		}
		if (min.right != null) {
			current = min.right;
			while (current.left != null) {
				current = current.left;
			}
		} else {
			return parentMin;
		}
		return current.value;
	}

	public static int getLastSecondMinRecursion(TreeNode root) {
		if (root == null || root.left == null) {
			throw new IllegalArgumentException("No elements");
		}
		if (root.left.left == null && root.left.right == null) {
			return root.value;
		}
		if (root.left.left != null) {
			return getLastSecondMinRecursion(root.left);
		}
		return getMin(root.left.right);
	}

	public static int getLastSecondMax(TreeNode root) {
		if (root == null) {
			throw new IllegalArgumentException("No elements");
		}
		TreeNode max = root;
		int parentMax = 0;
		TreeNode current = root;
		while (max.right != null) {
			parentMax = max.value;
			max = max.right;
		}
		if (max.left != null) {
			current = max.left;
			while (current.right != null) {
				current = current.right;
			}
		} else {
			return parentMax;
		}
		return current.value;
	}

	public static int getLastSecondMaxRecursion(TreeNode root) {
		if (root == null || root.right == null) {
			throw new IllegalArgumentException("No elements");
		}
		if (root.right.right == null && root.right.left == null) {
			return root.value;
		}
		if (root.right.right != null) {
			return getLastSecondMaxRecursion(root.right);
		}
		return getMax(root.right.left);
	}

	public static void printInOrder(TreeNode root) {
		if (root != null) {
			printInOrder(root.left);
			System.out.print(root.value + " ");
			printInOrder(root.right);
		}
	}
	
	public static void printPreOrder(TreeNode root) {
		if (root != null) {
			System.out.print(root.value + " ");
			printPreOrder(root.left);
			printPreOrder(root.right);
		}
	}
	
	public static void printPostOrder(TreeNode root) {
		if (root != null) {
			printPostOrder(root.left);
			printPostOrder(root.right);
			System.out.print(root.value + " ");
		}
	}
	
	//breath first search - layer by layer
	//depth first search - put in value, pop out, check if children from right to left, pop out, check if children from right to left and on and on...
}