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karths

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binary-10IQR-priority

like 0

ERROR: type should be string, got "https://leetcode.com/problems/binary-tree-level-order-traversal/description/\r\n\r\n* algorithms\r\n* Medium (48.77%)\r\n* Source Code: 102.binary-tree-level-order-traversal.py\r\n* Total Accepted: 487K\r\n* Total Submissions: 945.8K\r\n* Testcase Example: '[3,9,20,null,null,15,7]'\r\n\r\nGiven a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level\r\n).\r\n\r\n\r\nFor example:\r\nGiven binary tree `[3,9,20,null,null,15,7]`,\r\n\r\n```\r\n 3\r\n / \\\r\n 9 20\r\n / \\\r\n 15 7\r\n```\r\n\r\nreturn its level order traversal as:\r\n```\r\n[\r\n [3],\r\n [9,20],\r\n [15,7]\r\n]\r\n```\r\n\r\n### C++\r\n```cpp\r\nclass Solution {\r\npublic:\r\n vector<vector<int>> levelOrder(TreeNode* root) {\r\n vector<vector<int>> ans;\r\n DFS(root, 0, ans);\r\n return ans;\r\n }\r\nprivate:\r\n void DFS(TreeNode* root, int depth, vector<vector<int>>& ans) {\r\n if (!root) return;\r\n if (ans.size() <= depth) ans.push_back({});\r\n ans[depth].push_back(root->val);\r\n DFS(root->left, depth+1, ans);\r\n DFS(root->right, depth+1, ans);\r\n }\r\n};\r\n```\r\n\r\n### Python\r\n```python\r\nclass Solution:\r\n \"\"\"\r\n def levelOrder(self, root: TreeNode) -> List[List[int]]:\r\n res = []\r\n self.dfs(root, 0, res)\r\n return res\r\n # DFS\r\n def dfs(self, root, level, res):\r\n if not root:\r\n return \r\n if len(res) < level + 1:\r\n res.append([])\r\n res[level].append(root.val)\r\n self.dfs(root.left, level + 1, res)\r\n self.dfs(root.right, level + 1, res)\r\n \"\"\"\r\n \r\n \r\n def levelOrder(self, root: TreeNode) -> List[List[int]]:\r\n # BFS + queue\r\n res, queue = [], [(root, 0)]\r\n while queue:\r\n curr, level = queue.pop(0)\r\n if curr:\r\n if len(res) < level + 1:\r\n res.append([])\r\n res[level].append(curr.val)\r\n queue.append((curr.left, level+1))\r\n queue.append((curr.right, level+1))\r\n return res\r\n```"