100. same tree [相同的树]

描述

  Given two binary trees, write a function to check if they are the same or not.
  Two binary trees are considered the same if they are structurally identical and the nodes have the same value

  给定两个二叉树，编写一个函数来检验它们是否相同。
  如果两个树在结构上相同，并且节点具有相同的值，则认为它们是相同的

例子

思路

深度遍历/二叉树的先序遍历+递归

答案
python

class Solution:
    def isSameTree(self, p: TreeNode, q: TreeNode) -> bool:
        if not p and not q: #终止条件。如果p,q都不存在了
            return True
        if (not p or not q) or p.val != q.val:
            return False
        
        return self.isSameTree(p.left,q.left) and self.isSameTree(p.right,q.right)

java

class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if (p == null && q == null) //终止条件，两个节点都为空
            return true;
        if ((p == null || q == null) || p.val != q.val)
            return false;
        
        return isSameTree(p.left,q.left) && isSameTree(p.right, q.right);
        
    }
}