Problem Description
You want to water n plants in your garden with a watering can. The plants are arranged in a row and are labeled from 0 to n - 1 from left to right where the ith plant is located at x = i. There is a river at x = -1 that you can refill your watering can at.
Each plant needs a specific amount of water. You will water the plants in order from left to right. After watering the current plant, if you do not have enough water to completely water the next plant, return to the river to fully refill the watering can. You cannot refill the watering can early.
You are initially at the river (i.e., x = -1). It takes one step to move one unit on the x-axis.
Given a 0-indexed integer array plants of n integers, where plants[i] is the amount of water the ith plant needs, and an integer capacity representing the watering can capacity, return the number of steps needed to water all the plants.
Key Insights
- You start at the river and need to walk to each plant in order.
- Keep track of the remaining water in the can after watering each plant.
- If the remaining water is insufficient to water the next plant, return to the river to refill.
- Calculate the total steps taken, which includes steps to the plants and back to the river.
Space and Time Complexity
Time Complexity: O(n) - We iterate through the list of plants once. Space Complexity: O(1) - We use a constant amount of space for variables.
Solution
We will use a simple iterative approach to solve the problem. We will maintain a variable to track the current amount of water in the watering can. As we iterate through the plants, we will check if we have enough water to water the next plant. If not, we will count the steps back to the river to refill and then proceed to water the current plant. We will keep a running total of steps taken throughout the process.