Data Update

Task/Deceptive-numbers/Java/deceptive-numbers.java

@@ -0,0 +1,42 @@
+public final class DeceptiveNumbers {
+
+	public static void main(String[] aArgs) {
+		int n = 7;
+		int count = 0;
+		while ( count < 100 ) {
+			if ( isDeceptive(n) ) {
+				System.out.print(String.format("%6d%s", n, ( ++count % 10 == 0 ? "\n" : " " )));
+			}
+			n += 1;
+		}
+	}
+	
+	private static boolean isDeceptive(int aN) {
+		if ( aN % 2 != 0 && aN % 3 != 0 && aN % 5 != 0 && modulusPower(10, aN - 1, aN) == 1 ) {
+			for ( int divisor = 7; divisor < Math.sqrt(aN); divisor += 6 ) {
+				if ( aN % divisor == 0 || aN % ( divisor + 4 ) == 0 ) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+	
+	private static long modulusPower(long aBase, long aExponent, long aModulus) {
+	    if ( aModulus == 1 ) {
+	        return 0;
+	    }	
+	
+	    aBase %= aModulus;
+	    long result = 1;
+	    while ( aExponent > 0 ) {
+	        if ( ( aExponent  & 1 ) == 1 ) {
+	            result = ( result * aBase ) % aModulus;
+	        }
+	        aBase = ( aBase * aBase ) % aModulus;
+	        aExponent >>= 1;
+	    }
+	    return result;
+	}
+	
+}