Class Solution
Medium
You are given the root
of a binary tree with n
nodes. Each node is uniquely assigned a value from 1
to n
. You are also given an integer startValue
representing the value of the start node s
, and a different integer destValue
representing the value of the destination node t
.
Find the shortest path starting from node s
and ending at node t
. Generate step-by-step directions of such path as a string consisting of only the uppercase letters 'L'
, 'R'
, and 'U'
. Each letter indicates a specific direction:
'L'
means to go from a node to its left child node.'R'
means to go from a node to its right child node.'U'
means to go from a node to its parent node.
Return the step-by-step directions of the shortest path from node s
to node t
.
Example 1:
Input: root = [5,1,2,3,null,6,4], startValue = 3, destValue = 6
Output: “UURL”
Explanation: The shortest path is: 3 \u2192 1 \u2192 5 \u2192 2 \u2192 6.
Example 2:
Input: root = [2,1], startValue = 2, destValue = 1
Output: “L”
Explanation: The shortest path is: 2 \u2192 1.
Constraints:
- The number of nodes in the tree is
n
. 2 <= n <= 105
1 <= Node.val <= n
- All the values in the tree are unique.
1 <= startValue, destValue <= n
startValue != destValue
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionjava.lang.String
getDirections
(TreeNode root, int startValue, int destValue) Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Constructor Details
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Solution
public Solution()
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Method Details
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getDirections
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