- Difficulty: Medium
- Tags: LeetCode, Medium, Tree, Depth-First Search, Breadth-First Search, Binary Tree, leetcode-1430, O(n), O(h), 🔒, BFS, DFS, Stack
Problem
Given a binary tree where each path going from the root to any leaf form a valid sequence, check if a given string is a valid sequence in such binary tree.Â
We get the given string from the concatenation of an array of integers arr
and the concatenation of all values of the nodes along a path results in a sequence in the given binary tree.
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Example 1:
Input: root = [0,1,0,0,1,0,null,null,1,0,0], arr = [0,1,0,1] Output: true Explanation: The path 0 -> 1 -> 0 -> 1 is a valid sequence (green color in the figure). Other valid sequences are: 0 -> 1 -> 1 -> 0 0 -> 0 -> 0
Example 2:
Input: root = [0,1,0,0,1,0,null,null,1,0,0], arr = [0,0,1] Output: false Explanation: The path 0 -> 0 -> 1 does not exist, therefore it is not even a sequence.
Example 3:
Input: root = [0,1,0,0,1,0,null,null,1,0,0], arr = [0,1,1] Output: false Explanation: The path 0 -> 1 -> 1 is a sequence, but it is not a valid sequence.
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Constraints:
1 <= arr.length <= 5000
0 <= arr[i] <= 9
- Each node's value is between [0 - 9].