Given the root of a binary tree, each node has a value from 0 to 25 representing the letters 'a' to 'z': a value of 0 represents 'a', a value of 1 represents 'b', and so on. Find the lexicographically smallest string that starts at a leaf of this tre…

public class Solution { private Stack<string> ST = new Stack<string>(); private string SmallestStr = String.Empty; private string[] Ary = new string[] { "a","b","c","d","e","f","…