Resolve build errors & cleanup structure (#2334)

Strings/Pangram.java

@@ -0,0 +1,35 @@
+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;
+  }
+}