题解 | #每条路径的最大值#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @return int整型vector
     */
    vector<int> findMaxValues(TreeNode* root) {
        // write code here
        vector<int> res;
        if(!root){
            return res;
        }
        PreOrder(root,root->val,res);
        return res;
    }
    void PreOrder(TreeNode* root, int &max_val, vector<int> &res){
        if(root==nullptr)
            return;
        int temp_val = max_val;
        if(root->val > max_val){
            max_val = root->val;
        }
        if(root->left == nullptr && root->right == nullptr){
            res.emplace_back(max_val);
            max_val = temp_val;
        }
        PreOrder(root->left, max_val, res);
        PreOrder(root->right, max_val, res);
    }
};