chore(java): adjust skeleton

* add comments marking the regions
* adjust runner to take care of SINGLE v. MULTIPLE test cases

Signed-off-by: Matej Focko <me@mfocko.xyz>

.common/java/skeleton.java

@@ -9,35 +9,34 @@ import java.util.Random;
 import java.util.StringTokenizer;
 
 public class A {
-    private FastScanner fs = new FastScanner();
-    private PrintWriter out = new PrintWriter(System.out);
-
     void solve() {
         // TODO
     }
 
+    // region runner
+    private static final boolean SINGLE = false;
     void run() {
-        solve();
+        if (SINGLE) {
+            solve();
+        } else {
+            int N = fs.nextInt();
+            for (int i = 0; i < N; ++i) {
+                solve();
+            }
+        }
+
         out.close();
     }
 
     public static void main(String[] args) {
         new A().run();
     }
+    // endregion runner
 
+    // region math
     static final Random random = new Random();
     static final int mod = 1_000_000_007;
 
-    static void ruffleSort(int[] a) {
-        int n = a.length;// shuffle, then sort
-        for (int i = 0; i < n; i++) {
-            int oi = random.nextInt(n), temp = a[oi];
-            a[oi] = a[i];
-            a[i] = temp;
-        }
-        Arrays.sort(a);
-    }
-
     static long add(long a, long b) {
         return (a + b) % mod;
     }
@@ -74,6 +73,18 @@ public class A {
     static long nCk(int n, int k) {
         return mul(factorials[n], mul(invFactorials[k], invFactorials[n - k]));
     }
+    // endregion math
+
+    // region sorts
+    static void ruffleSort(int[] a) {
+        int n = a.length;// shuffle, then sort
+        for (int i = 0; i < n; i++) {
+            int oi = random.nextInt(n), temp = a[oi];
+            a[oi] = a[i];
+            a[i] = temp;
+        }
+        Arrays.sort(a);
+    }
 
     static void sort(int[] a) {
         ArrayList<Integer> l = new ArrayList<>();
@@ -83,7 +94,25 @@ public class A {
         for (int i = 0; i < a.length; i++)
             a[i] = l.get(i);
     }
+    // endregion sorts
 
+    // region output
+    private PrintWriter out = new PrintWriter(System.out);
+
+    private void yes() {
+        out.println("YES");
+    }
+
+    private void no() {
+        out.println("NO");
+    }
+
+    private void yesno(boolean ans) {
+        out.println(ans ? "YES" : "NO");
+    }
+    // endregion output
+
+    // region input
     static class FastScanner {
         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
         StringTokenizer st = new StringTokenizer("");
@@ -113,5 +142,7 @@ public class A {
             return Long.parseLong(next());
         }
     }
+    private FastScanner fs = new FastScanner();
+    // endregion input
 
 }