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[8/10] 108. Convert Sorted Array to Binary Search Tree
본문
Easy
7280385Add to ListShareGiven an integer array nums
where the elements are sorted in ascending order, convert it to a height-balanced binary search tree.
A height-balanced binary tree is a binary tree in which the depth of the two subtrees of every node never differs by more than one.
Example 1:
Input: nums = [-10,-3,0,5,9] Output: [0,-3,9,-10,null,5] Explanation: [0,-10,5,null,-3,null,9] is also accepted:
Example 2:
Input: nums = [1,3] Output: [3,1] Explanation: [1,null,3] and [3,1] are both height-balanced BSTs.
Constraints:
1 <= nums.length <= 104
-104 <= nums[i] <= 104
nums
is sorted in a strictly increasing order.
Accepted
804,149
Submissions
1,192,759
관련자료
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링크
댓글 3
학부유학생님의 댓글
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Runtime: 128 ms, faster than 52.36% of Python3 online submissions for Convert Sorted Array to Binary Search Tree.
Memory Usage: 15.6 MB, less than 32.22% of Python3 online submissions for Convert Sorted Array to Binary Search Tree.
Memory Usage: 15.6 MB, less than 32.22% of Python3 online submissions for Convert Sorted Array to Binary Search Tree.
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def sortedArrayToBST(self, nums: List[int]) -> Optional[TreeNode]:
def build_tree(arr):
if not arr: return None
mid = len(arr)//2
root = TreeNode(arr[mid])
root.left = build_tree(arr[:mid])
root.right = build_tree(arr[mid+1:])
return root
return build_tree(nums)
austin님의 댓글
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class Solution {
public:
TreeNode* sortedArrayToBST(vector<int>& nums) {
auto make = [](auto self, auto left, auto right) -> TreeNode* {
if (left == right) return nullptr;
auto mid = left + distance(left, right) / 2;
return new TreeNode(*mid, self(self, left, mid), self(self, next(mid), right));
};
return make(make, nums.begin(), nums.end());
}
};
재민재민님의 댓글
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Runtime: 20 ms, faster than 62.77% of C++ online submissions for Convert Sorted Array to Binary Search Tree.
Memory Usage: 21.4 MB, less than 40.73% of C++ online submissions for Convert Sorted Array to Binary Search Tree.
Memory Usage: 21.4 MB, less than 40.73% of C++ online submissions for Convert Sorted Array to Binary Search Tree.
class Solution {
public:
TreeNode* create_node(vector<int>& nums, int left, int right)
{
TreeNode* ans = NULL;
if(left == right)
{
ans = new TreeNode(nums[left]);
}
else if(left < right)
{
int mid = (right + left)/2;
ans = new TreeNode(nums[mid]);
ans->left = create_node(nums, left, mid-1);
ans->right = create_node(nums, mid+1, right);
}
return ans;
}
TreeNode* sortedArrayToBST(vector<int>& nums) {
TreeNode* ans = NULL;
int left = 0;
int right = nums.size()-1;
ans = create_node(nums, left, right);
return ans;
}
};