Same Tree 判断两棵树是不是相同

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.

判断两棵树是否一样是看：

1. 它们的当前节点值是否一样

2. 它们的左子树是否一样

3. 它们的右子树是否一样

递归解决

运行时间：

代码：

    public boolean isSameTree(TreeNode p, TreeNode q) {        if (p == null && q == null) {            return true;        } else if (p == null || q == null) {            return false;        } else {            return p.val == q.val && isSameTree(p.left, q.left) && isSameTree(p.right, q.right);        }    }