認識LeetCode樹的定義方式

/**
 * 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) {}
 * };
 */
 

94. 二叉樹的中序遍歷

vector <int>ans;
    vector<int> inorderTraversal(TreeNode* root) {
        dfs(root);
        return ans;

    }
    void dfs(TreeNode* root)
    {
        if(!root)return ;
        dfs(root->left);
        ans.push_back(root->val);
        dfs(root->right);
    }
 

100. 相同的樹

  bool isSameTree(TreeNode* p, TreeNode* q) {
        if(!p&&!q)return true;
        if(!p)return false;
        if(!q)return false;
        if(p->val!=q->val)return false;
        return isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);

    }