[leetcode]Same Tree

Same Tree

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.

算法思路：

思路1：判断两棵树是否一样，可以根据中序遍历+前（后）序遍历序列得到。

实现略。

思路2：dfs判断

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