Description
Given a binary tree and two node values, return the shortest path from start to destination as a string of U (up), L (left), R (right).
Examples
Input:
root = [5,1,2,3,null,6,4], startValue = 3, destValue = 6Output:
"UURL"Explanation:
Up twice, right, left.
Input:
root = [1,2,3,4,5,6,7], startValue = 4, destValue = 7Output:
UURExplanation:
Starting from node 4, go up to its parent node 2, then up again to the root node 1, then right to reach node 7. The path is: 4 → 2 → 1 → 3 → 7.
Input:
root = [8,3,10,1,6,null,14,null,null,4,7,13,null], startValue = 7, destValue = 13Output:
UUULExplanation:
Starting from node 7, go up to parent node 6, then up to parent node 3, then up to root node 8, then left to reach node 13. The path traverses: 7 → 6 → 3 → 8 → 10 → 14 → 13.
Constraints
- •
2 ≤ nodes ≤ 10⁵