[Algo Rhythm🕺💃] LeetCode 720. Longest Word in Dictionary

📚 Problem description

Given a list of strings words representing an English Dictionary, find 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".

 

Example 2:

Input:
words = ["a", "banana", "app", "appl", "ap", "apply", "apple"]
Output: "apple"
Explanation:
Both "apply" and "apple" can be built from other words in the dictionary. However, "apple" is lexicographically smaller than "apply".

 

Note:

• All the strings in the input will only contain lowercase letters.

• The length of words will be in the range [1, 1000].

• The length of words[i] will be in the range [1, 30].

 

🎯 Solution

 

🧐 Approach

The problem asks us to find the longest word in 'words' that can be built one character at a time by other words in 'words'.

 

This is related with prefix, so I built the trie. Then I checked if the word is prefix of another word or not. Then I compared the length and checked if the word can be answer or not.

 

📖  What I learned