Today I have done leetcode's September LeetCoding Challenge with cpp.

September LeetCoding Challenge 12

Description

Count the Number of Consistent Strings

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 <= 104
• 1 <= allowed.length <= 26
• 1 <= words[i].length <= 10
• The characters in allowed are distinct.
• words[i] and allowed contain only lowercase English letters.

Solution

class Solution {
public:
  int countConsistentStrings(string allowed, vector<string>& words) {
    set<int> cs(allowed.begin(), allowed.end());
    int answer = 0;
    for(const auto &word : words) {
      bool ok = true;
      for(auto c : word) {
        ok &= cs.count(c);
      }
      answer += ok;
    }
    return answer;
  }
};