is winning

minmax-java/src/main/java/ch/bbw/m411/connect4/Connect4ArenaMain.java

@@ -67,8 +67,65 @@ public class Connect4ArenaMain {
     }
 
     boolean isWinning(Stone[] board, Stone forColor) {
-		// TODO: provide an implementation
+        var increment = 0;
-		throw new IllegalStateException("Not implemented yet");
+        for (int i = 27; i >= 0; i--) {
+            if (forColor != board[i]) {
+                increment = 0;
+                continue;
+            }
+
+            // Horizontal reset
+            if (i == 20 || i == 13 || i == 6) {
+                increment = 0;
+            }
+
+            increment++;
+            // Horizontal
+            if (increment == 4) {
+                return true;
+            }
+
+            if (i > 20) {
+                // Vertical
+                var vertical = true;
+                for (int y = i - 7; y >= 0; y -= 7) {
+                    if (board[y] != forColor) {
+                        vertical = false;
+                        break;
+                    }
+                }
+                if (vertical) {
+                    return true;
+                }
+                // Diagonally
+                if (i <= 24) {
+                    var diagonal = true;
+                    for (int y = i; y >= 0; y -= 7 - 1) {
+                        if (board[y] != forColor) {
+                            diagonal = false;
+                            break;
+                        }
+                    }
+                    if (diagonal) {
+                        return true;
+                    }
+                }
+
+                if (i >= 24) {
+                    var diagonal = true;
+                    for (int y = i; y >= 0; y -= 7 + 1) {
+                        if (board[y] != forColor) {
+                            diagonal = false;
+                            break;
+                        }
+                    }
+                    if (diagonal) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
     }
 
     public enum Stone {
@@ -134,6 +191,7 @@ public class Connect4ArenaMain {
 
         /**
          * Givent the current {@link #board}, find a suitable position-index to play to.
+         *
          * @return the position to play to as defined by {@link Connect4Player#play(int)}.
          */
         protected abstract int play();
@@ -166,6 +224,7 @@ public class Connect4ArenaMain {
             }
             return sb.toString();
         }
+
         @Override
         protected int play() {
             System.out.println("where to to put the next " + myColor + "?");

minmax-java/src/main/java/ch/bbw/m411/connect4/RustPlayer.java

@@ -3,8 +3,6 @@ package ch.bbw.m411.connect4;
 public class RustPlayer extends Connect4ArenaMain.DefaultPlayer {
     private static native int rustPlay(byte player, byte[] board);
 
-    private static native boolean isWinning(byte player, byte[] forColor);
-
     static {
         // This actually loads the shared object that we'll be creating.
         // The actual location of the .so or .dll may differ based on your
@@ -29,15 +27,6 @@ public class RustPlayer extends Connect4ArenaMain.DefaultPlayer {
         return boardBuf;
     }
 
-    public static boolean isWinning(Connect4ArenaMain.Stone[] board, Connect4ArenaMain.Stone forColor) {
-        byte player = switch (forColor) {
-            case BLUE -> 0;
-            case RED -> 1;
-        };
-        byte[] boardBuf = RustPlayer.encodeBoard(board);
-        return RustPlayer.isWinning(player, boardBuf);
-    }
-
     @Override
     protected int play() {
         byte player = switch (this.myColor) {