all tasks

Task/Sierpinski-triangle/Java/sierpinski-triangle-1.java

@@ -0,0 +1,20 @@
+public static void triangle(int n){
+        n= 1 << n;
+        StringBuilder line= new StringBuilder(); //use a "mutable String"
+        char t= 0;
+        char u= 0; // avoid warnings
+        for(int i= 0;i <= 2 * n;++i)
+                line.append(" "); //start empty
+        line.setCharAt(n, '*'); //with the top point of the triangle
+        for(int i= 0;i < n;++i){
+                System.out.println(line);
+                u= '*';
+                for(int j= n - i;j < n + i + 1;++j){
+                        t= (line.charAt(j - 1) == line.charAt(j + 1) ? ' ' : '*');
+                        line.setCharAt(j - 1, u);
+                        u= t;
+                }
+                line.setCharAt(n + i, t);
+                line.setCharAt(n + i + 1, '*');
+        }
+}

Task/Sierpinski-triangle/Java/sierpinski-triangle-2.java

@@ -0,0 +1,27 @@
+import java.util.*;
+
+public class Sierpinski
+{
+    public static List<String> sierpinski(int n)
+    {
+        List<String> down = Arrays.asList("*");
+        String space = " ";
+        for (int i = 0; i < n; i++) {
+            List<String> newDown = new ArrayList<String>();
+            for (String x : down)
+                newDown.add(space + x + space);
+            for (String x : down)
+                newDown.add(x + " " + x);
+
+            down = newDown;
+            space += space;
+        }
+        return down;
+    }
+
+    public static void main(String[] args)
+    {
+        for (String x : sierpinski(4))
+            System.out.println(x);
+    }
+}