题目
检查两棵二叉树是否等价。等价的意思是说，首先两棵二叉树必须拥有相同的结构，并且每个对应位置上的节点上的数都相等。
分析
递归判断即可，较为简单
代码
/**
* Definition of TreeNode:
* public class TreeNode {
* public int val;
* public TreeNode left, right;
* public TreeNode(int val) {
* this.val = val;
* this.left = this.right = null;
* }
* }
*/
public class Solution {
/**
* @param a, b, the root of binary trees.
* @return true if they are identical, or false.
*/
public boolean isIdentical(TreeNode a, TreeNode b) {
// Write your code here
if (a == null && b == null)
return true;
if (a != null && b != null) {
return a.val == b.val && isIdentical(a.left, b.left)
&& isIdentical(a.right, b.right);
}
return false;
}
}
