个人记录-LeetCode 100. Same Tree

问题：

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.

这个问题比较简单，就是判断两颗树是否完全相等。

代码示例：

我们之间先序遍历比较一下即可。

代码类似于：

/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public boolean isSameTree(TreeNode p, TreeNode q) {
if (p == null && q == null) {
return true;
}

//先序遍历，先当前节点
//然后左子树，再右子树
if (p != null && q != null && p.val == q.val) {
return isSameTree(p.left, q.left)
&& isSameTree(p.right, q.right);
}

return false;
}
}