Formatted question description: https://leetcode.ca/all/1684.html
1684. Count the Number of Consistent Strings
Level
Easy
Description
You are given a string allowed
consisting of distinct characters and an array of strings words
. A string is consistent if all characters in the string appear in the string allowed
.
Return the number of consistent strings in the array words
.
Example 1:
Input: allowed = “ab”, words = [“ad”,”bd”,”aaab”,”baa”,”badab”]
Output: 2
Explanation: Strings “aaab” and “baa” are consistent since they only contain characters ‘a’ and ‘b’.
Example 2:
Input: allowed = “abc”, words = [“a”,”b”,”c”,”ab”,”ac”,”bc”,”abc”]
Output: 7
Explanation: All strings are consistent.
Example 3:
Input: allowed = “cad”, words = [“cc”,”acd”,”b”,”ba”,”bac”,”bad”,”ac”,”d”]
Output: 4
Explanation: Strings “cc”, “acd”, “ac”, and “d” are consistent.
Constraints:
1 <= words.length <= 10^4
1 <= allowed.length <= 26
1 <= words[i].length <= 10
- The characters in
allowed
are distinct. words[i]
andallowed
contain only lowercase English letters.
Solution
Use a set to store all the letters in allowed
. For each word
in words
, check whether all the letters in word
are in the set. If this is the case, increase the counter by 1. Finally, return the counter.
class Solution {
public int countConsistentStrings(String allowed, String[] words) {
Set<Character> set = new HashSet<Character>();
int length = allowed.length();
for (int i = 0; i < length; i++)
set.add(allowed.charAt(i));
int count = 0;
for (String word : words) {
boolean flag = true;
int wordLength = word.length();
for (int i = 0; i < wordLength; i++) {
if (!set.contains(word.charAt(i))) {
flag = false;
break;
}
}
if (flag)
count++;
}
return count;
}
}