                                      diff: diff,
                                        alpha: alpha,
                                        delta: xDelta
                                    });
                                }
                            }
                        }
                    }
                    if (possiblePosArr.length) {
                        // 如果仅通过 diff 判定出多个最优解，则还需要通过扩大mask的范围，一直到diff有唯一最小值
      