same-tree

/**
*
* @author gentleKay
* Given two binary trees, write a function to check if they are equal or not.
* Two binary trees are considered equal if they are structurally identical and the nodes have the same value.
*
* 给定两个二叉树，编写一个函数来检查它们是否相等。
* 如果两个二叉树的结构相同且节点具有相同的值，则认为它们是相等的。
*/

/**
 * 
 * @author gentleKay
 * Given two binary trees, write a function to check if they are equal or not.
 * Two binary trees are considered equal if they are structurally identical and the nodes have the same value.
 * 
 * 给定两个二叉树，编写一个函数来检查它们是否相等。
 * 如果两个二叉树的结构相同且节点具有相同的值，则认为它们是相等的。
 */

public class Main13 {
	public static void main(String[] args) {
		TreeNode root1 = new TreeNode(4);
		root1.left = new TreeNode(2);
		root1.left.left = new TreeNode(1);
		root1.left.right  = new TreeNode(3);
		
		root1.right = new TreeNode(6);
		root1.right.left = new TreeNode(5);
		root1.right.right = new TreeNode(7);
		root1.right.right.right = new TreeNode(8);
		
		TreeNode root2 = new TreeNode(4);
		root2.left = new TreeNode(2);
		root2.left.left = new TreeNode(1);
		root2.left.right  = new TreeNode(3);
		
		root2.right = new TreeNode(6);
		root2.right.left = new TreeNode(5);
		root2.right.right = new TreeNode(7);
//		root2.right.right.right = new TreeNode(8);
		
//		TreeNode root1 = null;
//		TreeNode root2 = new TreeNode(1);
		
		System.out.println(Main13.isSameTree(root1, root2));
	}
	
	public static class TreeNode {
		int val;
		TreeNode left;
		TreeNode right;
		TreeNode(int x) { val = x; }
	}
	
	public static boolean isSameTree(TreeNode p, TreeNode q) {
		if (p == null && q == null) {
			return true;
		}
		if (p == null || q == null) {
			return false;
		}
		if (p.val != q.val) {
			return false;
		}
		return isSameTree(p.left,q.left) && isSameTree(p.right,q.right);
    }
}