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.
代码如下：
1 /** 2 * Definition for a binary tree node. 3 * public class TreeNode { 4 * int val; 5 * TreeNode left; 6 * TreeNode right; 7 * TreeNode(int x) { val = x; } 8 * } 9 */ 10 public class Solution { 11 public boolean isSameTree(TreeNode p, TreeNode q) { 12 if(p==null&&q==null) 13 return true; 14 if(p!=null&&q!=null) 15 { 16 if(p.val==q.val&&isSameTree(p.left,q.left)&&isSameTree(p.right,q.right)) 17 return true; 18 } 19 return false; 20 } 21 }