Package g0901_1000.s0988_smallest_string_starting_from_leaf

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    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

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

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

      • Methods inherited from class java.lang.Object

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