872. Leaf-Similar Trees -E

Q:

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.

 

Constraints:

• Both of the given trees will have between 1 and 200 nodes.
• Both of the given trees will have values between 0 and 200

A:

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool leafSimilar(TreeNode* root1, TreeNode* root2) {
        vector<int> A,B;
        getLeaf(root1, A);
        getLeaf(root2, B);
        if(A.size() != B.size() )
            return false;
        for(int i =0;i<A.size(); ++i)
            if(A[i] != B[i])
                return false;
        return true;
    }
private:
    void getLeaf(const TreeNode *root, vector<int> &V){
        if(!root)
            return;
        if(! root->left  && ! root->right)
            V.push_back(root->val);
        if(root->left)
            getLeaf(root->left, V);
        if(root->right)
            getLeaf(root->right, V);
    }
};