1518. Water Bottles

Easy

There are numBottles water bottles that are initially full of water. You can exchange numExchange empty water bottles from the market with one full water bottle.

The operation of drinking a full water bottle turns it into an empty bottle.

Given the two integers numBottles and numExchange, return the maximum number of water bottles you can drink.

Example 1:

Input: numBottles = 9, numExchange = 3
Output:
 13
Explanation:
 You can exchange 3 empty bottles to get 1 full water bottle.
Number of water bottles you can drink: 9 + 3 + 1 = 13.

Example 2:

Input: numBottles = 15, numExchange = 4
Output:
 19
Explanation:
 You can exchange 4 empty bottles to get 1 full water bottle. 
Number of water bottles you can drink: 15 + 3 + 1 = 19.

Constraints:

• 1 <= numBottles <= 100

• 2 <= numExchange <= 100

解題

Runtime: 0 ms, faster than 100.00%

Memory Usage: 1.9 MB, less than 97.96%

func numWaterBottles(numBottles int, numExchange int) int {
    ans := 0
    empty := 0
    
    for numBottles>0 || empty >= numExchange {
        ans += numBottles
        empty += numBottles
        numBottles = empty/numExchange
        empty = empty%numExchange
    }
    
    return ans
}