{
  "analysis": "Now I see the distribution clearly. Most frames have only 4-7 changes, but some have 260-370 changes. For small-change frames, per-cell positioning works. For large-change frames, I need EL+rewrite. Let me calculate the optimal threshold.",
  "plan": "Calculate the optimal threshold for choosing between per-cell updates and EL+rewrite per row. Then implement the full solution.",
  "commands": [
    {
      "keystrokes": "python3 << 'PYEOF'\nimport struct\nfrom collections import Counter, defaultdict\n\nwith open('/app/frames.tza', 'rb') as f:\n    f.read(4)\n    w, h = struct.unpack('<HH', f.read(4))\n    n_frames, max_bytes = struct.unpack('<II', f.read(8))\n    frames = [f.read(w*h) for _ in range(n_frames)]\n\n# Analyze changes per row across all frames\nrow_change_stats = defaultdict(list)  # row -> list of change counts\n\nfor i in range(1, n_frames):\n    for r in range(h):\n        prev_row = frames[i-1][r*w:(r+1)*w]\n        curr_row = frames[i][r*w:(r+1)*w]\n        if prev_row != curr_row:\n            changes = sum(1 for c in range(w) if prev_row[c] != curr_row[c])\n            row_change_stats[r].append(changes)\n\nprint('Row change statistics:')\nfor r in sorted(row_change_stats.keys()):\n    counts = row_change_stats[r]\n    print(f'  Row {r}: {len(counts)} changes, min={min(counts)}, max={max(counts)}, avg={sum(counts)/len(counts):.1f}')\n\n# Calculate optimal cost with threshold\ndef pos_bytes(r, c):\n    return 3 + len(str(r)) + 1 + len(str(c))\n\ndef find_runs(changes):\n    runs = []\n    if not changes:\n        return runs\n    run_start = changes[0]\n    run_end = changes[0]\n    for c in changes[1:]:\n        if c == run_end + 1:\n            run_end = c\n        else:\n            runs.append((run_start, run_end))\n            run_start = run_end = c\n    runs.append((run_start, run_end))\n    return runs\n\n# Calculate cost for frame 0 (non-space only)\nframe0_cost = 0\nfor r in range(h):\n    row = frames[0][r*w:(r+1)*w]\n    non_space = [c for c in range(w) if row[c] != 32]\n    runs = find_runs(non_space)\n    for start, end in runs:\n        frame0_cost += pos_bytes(r+1, start+1) + (end - start + 1)\nframe0_cost += 1\nprint(f'\\nFrame 0 cost: {frame0_cost}')\n\n# Calculate cost for subsequent frames with optimal strategy per row\nrest_cost = 0\nfor i in range(1, n_frames):\n    for r in range(h):\n        prev_row = frames[i-1][r*w:(r+1)*w]\n        curr_row = frames[i][r*w:(r+1)*w]\n        if prev_row == curr_row:\n            continue\n        changes = [c for c in range(w) if prev_row[c] != curr_row[c]]\n        runs = find_runs(changes)\n        \n        # Cost of partial updates\n        partial_cost = sum(pos_bytes(r+1, start+1) + (end-start+1) for start, end in runs)\n        \n        # Cost of EL + rewrite\n        erase_cost = pos_bytes(r+1, 1) + 4 + w  # ESC[r;1H + ESC[2K + row\n        \n        # Choose cheaper\n        rest_cost += min(partial_cost, erase_cost)\n    rest_cost += 1  # delimiter\n\nprint(f'Frames 1+ cost (optimal per row): {rest_cost}')\nprint(f'Total: {frame0_cost + rest_cost}')\nprint(f'Budget: {max_bytes}')\nprint(f'Diff: {frame0_cost + rest_cost - max_bytes}')\nPYEOF\n",
      "duration": 5.0
    }
  ]
}