Algorithm
Problem Name: 720. Longest Word in Dictionary
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.
Note that the word should be built from left to right with each additional character being added to the end of a previous word.
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".
Constraints:
1 <= words.length <= 10001 <= words[i].length <= 30words[i]consists of lowercase English letters.
Code Examples
#1 Code Example with C++ Programming
Code -
C++ Programming
class Solution {
public:
string longestWord(vector<string>& words) {
string res = "";
unordered_map < int, unordered_set= res.size()) res = s.size() > res.size() ? s : min(s, res);
}
return res;
}
};
Input
Output
#2 Code Example with Javascript Programming
Code -
Javascript Programming
const longestWord = function(words) {
if(words == null || words.length === 0) return ''
words.sort()
const s = new Set()
let res = ''
for(let i = 0, len = words.length; i < len; i++) {
const w = words[i]
if(w.length === 1 || s.has(w.slice(0, w.length - 1))> {
res = w.length > res.length ? w : res
s.add(w)
}
}
return res
};
Input
Output
#3 Code Example with Python Programming
Code -
Python Programming
class Solution:
def longestWord(self, words):
"""
:type words: List[str]
:rtype: str
"""
for w in sorted(words, key = lambda x: (-len(x), x)):
if all([True if w[:i] in set(words) - {w} else False for i in range(1, len(w))]): return w
return ""
Input
Output
#4 Code Example with C# Programming
Code -
C# Programming
using System.Collections.Generic;
namespace LeetCode
{
public class _0720_LongestWordInDictionary
{
public string LongestWord(string[] words)
{
var root = new Trie() { Finished = true };
foreach (var word in words)
{
var current = root;
foreach (var ch in word)
{
if (current.Children[ch - 'a'] == null)
current.Children[ch - 'a'] = new Trie();
current = current.Children[ch - 'a'];
}
current.Finished = true;
current.Word = word;
}
var result = string.Empty;
var stack = new Stack < Trie>();
stack.Push(root);
while (stack.Count > 0)
{
var node = stack.Pop();
if (node.Finished)
{
if (node.Word.Length >= result.Length)
result = node.Word;
for (int i = 0; i < 26; i++)
{
if (node.Children[i] != null)
stack.Push(node.Children[i]);
}
}
}
return result;
}
public class Trie
{
public Trie[] Children = new Trie[26];
public bool Finished = false;
public string Word = string.Empty;
}
}
}
Input
Output