Just another update

Task/Yin-and-yang/Java/yin-and-yang-2.java

@@ -0,0 +1,82 @@
+import java.util.Collection;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.BooleanSupplier;
+import java.util.function.Supplier;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+import static java.util.Collections.singletonMap;
+
+public interface YinYang {
+  public static boolean circle(
+    int x,
+    int y,
+    int c,
+    int r
+  ) {
+    return
+      (r * r) >=
+        ((x = x / 2) * x)
+         + ((y = y - c) * y)
+    ;
+  }
+
+  public static String pixel(int x, int y, int r) {
+    return Stream.<Map<BooleanSupplier, Supplier<String>>>of(
+      singletonMap(
+        () -> circle(x, y, -r / 2, r / 6),
+        () -> "#"
+      ),
+      singletonMap(
+        () -> circle(x, y, r / 2, r / 6),
+        () -> "."
+      ),
+      singletonMap(
+        () -> circle(x, y, -r / 2, r / 2),
+        () -> "."
+      ),
+      singletonMap(
+        () -> circle(x, y, r / 2, r / 2),
+        () -> "#"
+      ),
+      singletonMap(
+        () -> circle(x, y, 0, r),
+        () -> x < 0 ? "." : "#"
+      )
+    )
+      .sequential()
+      .map(Map::entrySet)
+      .flatMap(Collection::stream)
+      .filter(e -> e.getKey().getAsBoolean())
+      .map(Map.Entry::getValue)
+      .map(Supplier::get)
+      .findAny()
+      .orElse(" ")
+    ;
+  }
+
+  public static void yinYang(int r) {
+    IntStream.rangeClosed(-r, r)
+      .mapToObj(
+        y ->
+          IntStream.rangeClosed(
+            0 - r - r,
+            r + r
+          )
+            .mapToObj(x -> pixel(x, y, r))
+            .reduce("", String::concat)
+      )
+      .forEach(System.out::println)
+    ;
+  }
+
+  public static void main(String... arguments) {
+    Optional.of(arguments)
+      .filter(a -> a.length == 1)
+      .map(a -> a[0])
+      .map(Integer::parseInt)
+      .ifPresent(YinYang::yinYang)
+    ;
+  }
+}