按序记录每棵树叶子节点。比较是否一致。

前序，中序，后序都可以。

Consider all the leaves of a binary tree.  From left to right order, the values of those leaves form a leaf value sequence.

For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8).

Two binary trees are considered leaf-similar if their leaf value sequence is the same.

Return true if and only if the two given trees with head nodes root1 and root2 are leaf-similar.

 

Note:

• Both of the given trees will have between 1 and 100 nodes.

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    bool leafSimilar(TreeNode* root1, TreeNode* root2) {        vector
     
       res1;        vector
      
        res2;        preorder(root1,res1);        preorder(root2,res2);        if(res1.size()!=res2.size())            return false;        for(int i=0;i
       

& res){ if(root==NULL) return; if(root->left==NULL && root->right==NULL){ res.push_back(root->val); return; } preorder(root->left,res); preorder(root->right,res); }};