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Solving Leetcode Interviews in Seconds with AI: Water Bottles II

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3 min read

Introduction

In this blog post, we will explore how to solve the LeetCode problem "3100" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

You are given two integers numBottles and numExchange. numBottles represents the number of full water bottles that you initially have. In one operation, you can perform one of the following operations: Drink any number of full water bottles turning them into empty bottles. Exchange numExchange empty bottles with one full water bottle. Then, increase numExchange by one. Note that you cannot exchange multiple batches of empty bottles for the same value of numExchange. For example, if numBottles == 3 and numExchange == 1, you cannot exchange 3 empty water bottles for 3 full bottles. Return the maximum number of water bottles you can drink. Example 1: Input: numBottles = 13, numExchange = 6 Output: 15 Explanation: The table above shows the number of full water bottles, empty water bottles, the value of numExchange, and the number of bottles drunk. Example 2: Input: numBottles = 10, numExchange = 3 Output: 13 Explanation: The table above shows the number of full water bottles, empty water bottles, the value of numExchange, and the number of bottles drunk. Constraints: 1 <= numBottles <= 100 1 <= numExchange <= 100

Explanation

Here's an efficient solution to the water bottle exchange problem:

  • Core Idea: Simulate the drinking and exchanging process. Track the number of full bottles, empty bottles, and the increasing exchange rate. Keep drinking bottles and exchanging empty ones until we no longer have enough empty bottles for an exchange.
  • Optimization: Instead of incrementing numExchange with each exchange, we can calculate the number of new bottles and updated exchange rate within the loop, streamlining the process. This avoids the need for repeated increments and makes the loop condition clearer.

  • Complexity:

    • Runtime: O(n), where n is the number of exchanges. In the worst case, the number of exchanges is proportional to the initial number of bottles. However, given the constraints (1 <= numBottles <= 100, 1 <= numExchange <= 100), the loop will execute a limited number of times, making the algorithm efficient.
    • Storage: O(1) - We use a constant amount of extra space.

Code

    def max_water_bottles(numBottles: int, numExchange: int) -> int:
    """
    Calculates the maximum number of water bottles that can be drunk.

    Args:
        numBottles: The initial number of full water bottles.
        numExchange: The initial number of empty bottles required for an exchange.

    Returns:
        The maximum number of water bottles that can be drunk.
    """

    drunk_bottles = numBottles
    empty_bottles = numBottles

    while empty_bottles >= numExchange:
        new_bottles = empty_bottles // numExchange
        drunk_bottles += new_bottles
        empty_bottles = empty_bottles % numExchange + new_bottles

    return drunk_bottles

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