872.Leaf-Similar Trees

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.

##先深度搜索，然后再存到vector里面
class Solution {
public:
    bool leafSimilar(TreeNode* root1, TreeNode* root2) {  
        vector<int> v1,v2;
        dfs(root1,v1);
        dfs(root2,v2);
        return v1==v2;    
    }
    
    void dfs(TreeNode *root,vector<int>& v)
    {
        if(root==NULL) return;
        if(root->left==NULL && root->right==NULL)
            v.push_back(root->val);
        dfs(root->left,v);
        dfs(root->right,v);       
    }
};