Code toolkit

sketchbook/test_toolkit/CodeToolkit.pde

+class CodeToolkit {
+  // Count vectors. Used locally in _feedback() but defined here for performance reasons
+  int[] d1 = new int[C];
+  int[] d2 = new int[C];
+  // Precomputed feedback matrix
+  int[][] feedbacks = new int[M][M];
+  
+  CodeToolkit() {
+    // Precomputing feedbacks
+    for (int code1 = 0; code1 < M; code1++) {
+      for (int code2 = code1; code2 < M; code2++) {
+        feedbacks[code1][code2] = feedbacks[code2][code1] = _feedback(code1, code2);
+      }
+    }
+  }
+  
+  int feedback(int code, int guess) {
+    return feedbacks[code][guess];
+  }
+  
+  void decodeFeedback(int f, int[] bw) {
+    int s = 0;
+    int i = 0;
+    while (s + i <= f) {
+      s += i;
+      i++;
+    }
+    i--;
+    bw[0] = N - i;
+    bw[1] = f - s;
+  }
+  
+  String codeToString(int code) {
+    String s = "";
+    for (int i = 0; i < N; i++) {
+      s = code % C + s;
+      code /= C;
+    }
+    return s;
+  }
+  
+  void displayCode(int code, int x, int y, int pegSize, boolean eliminated) {
+    stroke(0);
+    rectMode(CORNER);
+    colorMode(HSB, C, 1, 1, 1);
+    for (int i = N - 1; i >= 0; i--) {
+      int c = code % C;
+      fill(color(c, 1, 1, eliminated ? 0.25 : 1));
+      rect(x + i * pegSize, y, pegSize, pegSize);
+      code /= C;
+    }
+    colorMode(RGB, 255, 255, 255, 255);
+  }
+  
+  int _encodeFeedback(int black, int white) {
+    return (N - black) * (N - black + 1) / 2 + white;
+  }
+  
+  int _feedback(int code1, int code2) {
+    for (int c = 0; c < C; c++) {
+      d1[c] = d2[c] = 0;
+    }
+    int black = 0;
+    for (int i = 0; i < N; i++) {
+      int c1 = code1 % C;
+      int c2 = code2 % C;
+      if (c1 == c2) {
+        black++;
+      } else {
+        d1[c1]++;
+        d2[c2]++;
+      }
+      code1 /= C;
+      code2 /= C;
+    }
+    int white = 0;
+    for (int c = 0; c < C; c++) {
+      white += min(d1[c], d2[c]);
+    }
+    return _encodeFeedback(black, white);
+  }
+}

sketchbook/test_toolkit/test_toolkit.pde

+final int N = 4; // Code length
+final int C = 6; // Number of colors
+
+final int M = round(pow(C, N)); // Number of possible codes
+final int F = (N + 1) * (N + 2) / 2; // Number of possible feedbacks
+
+CodeToolkit tk = new CodeToolkit();
+
+final int PEG_SIZE = 40;
+final int GAP = 10;
+
+int code;
+int t;
+
+void setup() {
+  size(310, 560);
+  background(191);
+  code = int(random(M));
+  tk.displayCode(code, GAP, GAP, PEG_SIZE, false);
+  t = 0;
+}
+
+void draw() {
+  t++;
+  int guess = int(random(M));
+  int y = GAP + (GAP + PEG_SIZE) * t;
+  tk.displayCode(guess, GAP, y, PEG_SIZE, false);
+  int f = tk.feedback(code, guess);
+  displayFeedback(f, 2 * GAP + N * PEG_SIZE, y + PEG_SIZE / 4);
+  if (f == 0 || t == 10) noLoop();
+}
+
+void displayFeedback(int f, int x, int y) {
+  int[] bw = new int[2];
+  tk.decodeFeedback(f, bw);
+  stroke(0);
+  for (int k = 0; k < bw[0] + bw[1]; k++) {
+    fill(k < bw[0] ? 0: 255);
+    rect(x, y, PEG_SIZE / 2, PEG_SIZE / 2);
+    x += PEG_SIZE / 2 + GAP;
+  }
+}