IOS开发-影院选座算法 限制产生孤座

众所周知目前影院选座是不允许随便选的，我们不可以任性的挑三拣四，最后留下N个单独的座位，目的就是要留下至少2个连着的座位；

另外有些影院的座位摆放并不是规则的，有些座位被过道或者特殊座位分割开，产生了不同的分区，这里就实现检测有没有座位变成了孤座，

孤座的含义简单说就是两个小情侣不能挨着坐了~

但是也存在特殊情况，及因为分区的缘故，某一排连着的座位只有2个，或者只有3个，这时候还是可以允许人家买其中之一，或者之二的~

好，条件说完之后，开始介绍数据结构，正常情况下，影院的每一个座位数据会包含坐标，座位号，如x，y，row，column。

其中，影厅中的面积会以单个座位的大小被分割成M*N的坐标系，即过道也有它的坐标；而row和column才是真正的座位；

啰嗦了半天，下面上代码：

入口函数是verifySelectedSeatsWithSeatsDic，

　　1. 参数seatsDic是一个字典，注意该字典过滤掉了非座位的数据！（字典是本项目所需，你可以直接用一个array，方法中我也是获取了array；注意座位数据的顺序一定是有序的，这样才能获取到一个座位的左右座位）

　　2. 每个座位的数据我封装成了一个WCSeatButton，并提供了isSeatAvailable方法判断该座位是否可以被购买（未被售出）

　　3. 函数getNearBySeatsInSameRowForSeat负责获取没有被过道等非座位隔开的所有座位

 　  4. 函数(BOOL)isSeat:(WCSeatButton *)s1 nearBySeatWithoutRoad:(WCSeatButton *)s2判断两个座位是否被过道隔开

-(BOOL)verifySelectedSeatsWithSeatsDic:(NSDictionary *)seatsDic {
    NSArray *seatBtns = [seatsDic allValues];
    if ([seatBtns count] > 0) {
        for (WCSeatButton *btn in seatBtns) {
            //查看可选座位是否落单
            if([btn isSeatAvailable]){
                int idx = btn.seatIndex;

                WCSeatButton *preBtn = [seatsDic objectForKey:[NSString stringWithFormat:@"%i", idx - 1]];
                WCSeatButton *nextBtn = [seatsDic objectForKey:[NSString stringWithFormat:@"%i", idx + 1]];

                //检验是否存在相邻座位 and 可用
                BOOL isPreOK = preBtn != nil &&
                        [preBtn.serviceSeat.row isEqualToString:btn.serviceSeat.row] &&
                        [preBtn isSeatAvailable];
                BOOL isNextOK = nextBtn != nil &&
                        [nextBtn.serviceSeat.row isEqualToString:btn.serviceSeat.row]&&
                        [nextBtn isSeatAvailable] ;

                //再判断同一分区
                if (isPreOK) {
                    isPreOK =  ABS([btn.serviceSeat.yCoord intValue] - [preBtn.serviceSeat.yCoord intValue]) == 1;

                }
                if (isNextOK) {
                    isNextOK = ABS([btn.serviceSeat.yCoord intValue] - [nextBtn.serviceSeat.yCoord intValue]) == 1;

                }

                if (!isPreOK && !isNextOK) {
                    NSArray *nearBySeats = [self getNearBySeatsInSameRowForSeat:btn withSeatsDic:seatsDic];
                    //例外 两个座位只选一个
                    if ([nearBySeats count] == 2) {
                        continue;
                    }
                    //例外 3个座位中2个连续被选，剩下单个座位
                    if ([nearBySeats count] == 3) {
                        int idx = [nearBySeats indexOfObject:btn];
                        //空座位如果在两边说明中间的座位已经被选，则只要还有一个被选就可以
                        if (idx == 0 && ![nearBySeats[2] isSeatAvailable]) {
                            continue;
                        }else if(idx == 2 && ![nearBySeats[0] isSeatAvailable]) {
                            continue;
                        }
                    }

                    //只限制当前用户选择的座位，防止其他渠道产生孤座导致当前用户不能选座
                    for (WC630ServiceSeat *s in self.orderItem.seats) {
                         if((preBtn && [[[preBtn serviceSeat] cineSeatId] isEqualToString:s.cineSeatId]) ||
                                 (nextBtn && [[[nextBtn serviceSeat] cineSeatId] isEqualToString:s.cineSeatId])    ) {
                             return NO;
                         }
                    }
                }


            }
        }
    }

    return YES;
}

-(NSArray *)getNearBySeatsInSameRowForSeat:(WCSeatButton *)seat withSeatsDic:(NSDictionary *)seatsDic{
    NSMutableArray *result = [NSMutableArray array];
    [result addObject:seat];

    int idx = seat.seatIndex - 1;
    //left
    WCSeatButton *tmp= [seatsDic objectForKey:[NSString stringWithFormat:@"%i", idx]];
    while([self isSeat:tmp nearBySeatWithoutRoad:seat]){
        [result insertObject:tmp atIndex:0];
        idx--;
        tmp = [seatsDic objectForKey:[NSString stringWithFormat:@"%i", idx]];
    }

    idx = seat.seatIndex + 1;
    //right
    tmp= [seatsDic objectForKey:[NSString stringWithFormat:@"%i", idx]];
    while([self isSeat:tmp nearBySeatWithoutRoad:seat]){
        [result addObject:tmp];
        idx++;
        tmp = [seatsDic objectForKey:[NSString stringWithFormat:@"%i", idx]];
    }


    return result;
}

-(BOOL)isSeat:(WCSeatButton *)s1 nearBySeatWithoutRoad:(WCSeatButton *)s2{

    return     s1 != nil &&
            [s1.serviceSeat.row isEqualToString:s2.serviceSeat.row] &&
            ABS([s1.serviceSeat.yCoord intValue] - [s2.serviceSeat.yCoord intValue]) == ABS([s1.serviceSeat.column intValue] - [s2.serviceSeat.column intValue]) ;
}