JavaAlgorithms/strings/Pangram.java

package strings;

/** Wikipedia: https://en.wikipedia.org/wiki/Pangram */
public class Pangram {

  /** Driver Code */
  public static void main(String[] args) {
    assert isPangram("The quick brown fox jumps over the lazy dog");
    assert !isPangram("The quick brown fox jumps over the azy dog"); /* not exists l character */
  }

  /**
   * Check if a string is a pangram string or not
   *
   * @param s string to check
   * @return {@code true} if given string is pangram, otherwise {@code false}
   */
  public static boolean isPangram(String s) {
    boolean[] marked = new boolean[26]; /* by default all letters don't exists */
    char[] values = s.toCharArray();
    for (char value : values) {
      if (Character.isLetter(value)) {
        int index = Character.isUpperCase(value) ? value - 'A' : value - 'a';
        marked[index] = true; /* mark current character exists */
      }
    }

    for (boolean b : marked) {
      if (!b) {
        return false;
      }
    }
    return true;
  }
}