int numWaterBottles(int numBottles, int numExchange){
int total = 0;
int spaceBottels = 0;
while(numBottles)
{
total+=numBottles;
spaceBottels = numBottles + spaceBottels; //喝完之后加上之前的空瓶
numBottles = spaceBottels / numExchange; //空瓶除以换瓶数得到新瓶数
spaceBottels = spaceBottels % numExchange; //换瓶后剩余空瓶
}
return total;
}