Given an array of strings words representing an English Dictionary, return the longest word in words that can be built one character at a time by other words in words.
If there is more than one possible answer, return the longest word with the smallest lexicographical order. If there is no answer, return the empty string.
Example 1:
Input: words = ["w","wo","wor","worl","world"]
Output: "world"
Explanation: The word "world" can be built one character at a time by "w", "wo", "wor", and "worl".
I knew that the best solution is “Tire”. But, I used Hash first and that is method of brute force. I will used “Tire” later.
Sort first. check the word with hashset one by one. If those words are include in hashset, I will compare length of result and the word, and replace result to longer word.
我知道這題的最佳解是用Tire，先使用Hash的方式解這題，之後會再用Tire解一次，先來說明暴力解的方式。
暴力解:
先做排序，逐一檢查每個字的前面字串是否有存在hash裡面。如果沒有，就表示這個字串並不符合。如果有，則檢查是否為最長的字。