Change project structure to a Maven Java project + Refactor (#2816)

src/main/java/com/thealgorithms/strings/Pangram.java

@@ -0,0 +1,42 @@
+package com.thealgorithms.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;
+    }
+}