g0901_1000.s0988_smallest_string_starting_from_leaf

Class Solution

java.lang.Object

g0901_1000.s0988_smallest_string_starting_from_leaf.Solution

public class Solution
extends Object

988 - Smallest String Starting From Leaf.

Medium

You are given the root of a binary tree where each node has a value in the range [0, 25] representing the letters 'a' to 'z'.

Return the lexicographically smallest string that starts at a leaf of this tree and ends at the root.

As a reminder, any shorter prefix of a string is lexicographically smaller.

• For example, "ab" is lexicographically smaller than "aba".

A leaf of a node is a node that has no children.

Example 1:

Input: root = [0,1,2,3,4,3,4]

Output: “dba”

Example 2:

Input: root = [25,1,3,1,3,0,2]

Output: “adz”

Example 3:

Input: root = [2,2,1,null,1,0,null,0]

Output: “abc”

Constraints:

• The number of nodes in the tree is in the range [1, 8500].
• 0 <= Node.val <= 25

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
String	smallestFromLeaf(TreeNode root)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

smallestFromLeaf

public String smallestFromLeaf(TreeNode root)