366. Find Leaves of Binary Tree - cocoder39/coco39_LC GitHub Wiki

class Solution:
    def findLeaves(self, root: Optional[TreeNode]) -> List[List[int]]:
        res = []
        self.getHeight(root, res)
        return res

    def getHeight(self, root: Optional[TreeNode], res: List[List[int]]) -> int:
        if not root:
            return -1
        
        height = max(self.getHeight(root.left, res), self.getHeight(root.right, res)) + 1
        
        if len(res) == height:
            res.append([])
        
        res[height].append(root.val)
        
        return height

class Solution {
public:
    vector<vector<int>> findLeaves(TreeNode* root) {
        vector<vector<int>> res;
        helper(res, root);
        return res;
    }
private:
    int helper(vector<vector<int>>& res, TreeNode* root) {
        if (! root) {
            return 0;
        }
       
        int level = max(helper(res, root->left), helper(res, root->right)) + 1;
        if (res.size() < level)
            res.push_back(vector<int>());
        res[level - 1].push_back(root->val);
        return level;
    }
};