- Difficulty: Medium
- Tags: LeetCode, Medium, Tree, Depth-First Search, Breadth-First Search, Design, Hash Table, Binary Tree, leetcode-1261, O(n), O(h), DFS
Problem
Given a binary tree with the following rules:
root.val == 0
- If
treeNode.val == x
andtreeNode.left != null
, thentreeNode.left.val == 2 * x + 1
- If
treeNode.val == x
andtreeNode.right != null
, thentreeNode.right.val == 2 * x + 2
Now the binary tree is contaminated, which means all treeNode.val
have been changed to -1
.
Implement the FindElements
class:
FindElements(TreeNode* root)
Initializes the object with a contaminated binary tree and recovers it.bool find(int target)
Returnstrue
if thetarget
value exists in the recovered binary tree.
Example 1:
Input ["FindElements","find","find"] [[[-1,null,-1]],[1],[2]] Output [null,false,true] Explanation FindElements findElements = new FindElements([-1,null,-1]); findElements.find(1); // return False findElements.find(2); // return True
Example 2:
Input ["FindElements","find","find","find"] [[[-1,-1,-1,-1,-1]],[1],[3],[5]] Output [null,true,true,false] Explanation FindElements findElements = new FindElements([-1,-1,-1,-1,-1]); findElements.find(1); // return True findElements.find(3); // return True findElements.find(5); // return False
Example 3:
Input ["FindElements","find","find","find","find"] [[[-1,null,-1,-1,null,-1]],[2],[3],[4],[5]] Output [null,true,false,false,true] Explanation FindElements findElements = new FindElements([-1,null,-1,-1,null,-1]); findElements.find(2); // return True findElements.find(3); // return False findElements.find(4); // return False findElements.find(5); // return True
Constraints:
TreeNode.val == -1
- The height of the binary tree is less than or equal to
20
- The total number of nodes is between
[1, 104]
- Total calls of
find()
is between[1, 104]
0 <= target <= 106