1684 - Count the Number of Consistent Strings

 C++

• class Solution {
  public:
      int countConsistentStrings(string allowed, vector<string>& words) {
          bitset<26> s;
          for (auto& c : allowed) s[c - 'a'] = 1;
          int ans = 0;
          auto check = [&](string& w) {
              for (auto& c : w)
                  if (!s[c - 'a']) return false;
              return true;
          };
          for (auto& w : words) ans += check(w);
          return ans;
      }
  };

JAVA

• class Solution {
      public int countConsistentStrings(String allowed, String[] words) {
          boolean[] s = new boolean[26];
          for (char c : allowed.toCharArray()) {
              s[c - 'a'] = true;
          }
          int ans = 0;
          for (String w : words) {
              if (check(w, s)) {
                  ++ans;
              }
          }
          return ans;
      }
  
      private boolean check(String w, boolean[] s) {
          for (int i = 0; i < w.length(); ++i) {
              if (!s[w.charAt(i) - 'a']) {
                  return false;
              }
          }
          return true;
      }
  }