* add LucasSeries

* add PerfectCube
* PerfectSquare

Maths/PerfectSquare.java

@@ -0,0 +1,25 @@
+package Maths;
+
+/**
+ * https://en.wikipedia.org/wiki/Perfect_square
+ */
+public class PerfectSquare {
+    public static void main(String[] args) {
+        assert !isPerfectSquare(-1);
+        assert !isPerfectSquare(3);
+        assert !isPerfectSquare(5);
+        assert isPerfectSquare(9);
+        assert isPerfectSquare(100);
+    }
+
+    /**
+     * Check if a number is perfect square number
+     *
+     * @param number the number to be checked
+     * @return <tt>true</tt> if {@code number} is perfect square, otherwise <tt>false</tt>
+     */
+    public static boolean isPerfectSquare(int number) {
+        int sqrt = (int) Math.sqrt(number);
+        return sqrt * sqrt == number;
+    }
+}