LeetCode 솔루션 분류
[7/14] 105. Construct Binary Tree from Preorder and Inorder Traversal
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Medium
9289255Add to ListShareGiven two integer arrays preorder and inorder where preorder is the preorder traversal of a binary tree and inorder is the inorder traversal of the same tree, construct and return the binary tree.
Example 1:
Input: preorder = [3,9,20,15,7], inorder = [9,3,15,20,7] Output: [3,9,20,null,null,15,7]
Example 2:
Input: preorder = [-1], inorder = [-1] Output: [-1]
Constraints:
1 <= preorder.length <= 3000inorder.length == preorder.length-3000 <= preorder[i], inorder[i] <= 3000preorderandinorderconsist of unique values.- Each value of
inorderalso appears inpreorder. preorderis guaranteed to be the preorder traversal of the tree.inorderis guaranteed to be the inorder traversal of the tree.
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Runtime: 335 ms, faster than 21.08% of Python3 online submissions for Construct Binary Tree from Preorder and Inorder Traversal.
Memory Usage: 88.7 MB, less than 25.00% of Python3 online submissions for Construct Binary Tree from Preorder and Inorder Traversal.
Memory Usage: 88.7 MB, less than 25.00% of Python3 online submissions for Construct Binary Tree from Preorder and Inorder Traversal.
class Solution:
def buildTree(self, preorder: List[int], inorder: List[int]) -> Optional[TreeNode]:
if not preorder or not inorder: return None
root = TreeNode(preorder[0])
pivot = inorder.index(root.val)
root.left = self.buildTree(preorder[1:pivot+1], inorder[:pivot])
root.right = self.buildTree(preorder[pivot+1:], inorder[pivot+1:])
return root
