Algorithm
Problem Name: 500. Keyboard Row
Given an array of strings words, return the words that can be typed using letters of the alphabet on only one row of American keyboard like the image below.
In the American keyboard:
- the first row consists of the characters
"qwertyuiop", - the second row consists of the characters
"asdfghjkl", and - the third row consists of the characters
"zxcvbnm".
Example 1:
Input: words = ["Hello","Alaska","Dad","Peace"] Output: ["Alaska","Dad"]
Example 2:
Input: words = ["omk"] Output: []
Example 3:
Input: words = ["adsdf","sfd"] Output: ["adsdf","sfd"]
Constraints:
1 <= words.length <= 201 <= words[i].length <= 100words[i]consists of English letters (both lowercase and uppercase).
Code Examples
#1 Code Example with Java Programming
Code -
Java Programming
class Solution {
public String[] findWords(String[] words) {
Map map = new HashMap<>();
update(map, "qwertyuiop", 1);
update(map, "asdfghjkl", 2);
update(map, "zxcvbnm", 3);
List < Integer> list = new ArrayList<>();
for (int i = 0; i < words.length; i++) {
int rowIdx = -1;
for (char c : words[i].toCharArray()) {
if (rowIdx == -1) {
rowIdx = map.get(Character.toLowerCase(c));
}
if (map.get(Character.toLowerCase(c)) != rowIdx) {
rowIdx = -1;
break;
}
}
if (rowIdx != -1) {
list.add(i);
}
}
String[] ans = new String[list.size()];
for (int i = 0; i < list.size(); i++) {
ans[i] = words[list.get(i)];
}
return ans;
}
private void update(Map < Character, Integer> map, String s, int row) {
for (char c : s.toCharArray()) {
map.put(c, row);
}
}
}
Input
words = ["Hello","Alaska","Dad","Peace"]
Output
["Alaska","Dad"]
#2 Code Example with Javascript Programming
Code -
Javascript Programming
const findWords = function(words) {
const regex = /^[qwertyuiop]*$|^[asdfghjkl]*$|^[zxcvbnm]*$/;
return words.filter(
s => (s.toLowerCase().match(regex) === null ? false : true)
);
};
console.log(findWords(["Hello", "Alaska", "Dad", "Peace"]));
Input
words = ["Hello","Alaska","Dad","Peace"]
Output
["Alaska","Dad"]
#3 Code Example with Python Programming
Code -
Python Programming
class Solution:
def findWords(self, words):
return [w for w in words if any(not set(w.lower()) - row for row in (set("qwertyuiop"), set("asdfghjkl"), set("zxcvbnm")))]
Input
words = ["omk"]
Output
[]
#4 Code Example with C# Programming
Code -
C# Programming
using System.Collections.Generic;
namespace LeetCode
{
public class _0500_KeyboardRow
{
public string[] FindWords(string[] words)
{
if (words.Length == 0) return words;
var map = new Dictionary < char, int>();
string r1 = "qwertyuiopQWERTYUIOP";
foreach (var ch in r1)
map[ch] = 1;
string r2 = "asdfghjklASDFGHJKL";
foreach (var ch in r2)
map[ch] = 2;
string r3 = "zxcvbnmZXCVBNM";
foreach (var ch in r3)
map[ch] = 3;
var result = new List < string>();
foreach (var word in words)
{
var flag = map[word[0]];
var valid = true;
foreach (var ch in word)
{
if (flag != map[ch])
{
valid = false;
break;
}
}
if (valid)
result.Add(word);
}
return result.ToArray();
}
}
}
Input
words = ["omk"]
Output
[]