How do you solve Watering Plants on LeetCode?

Watering Plants (LeetCode #2079) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(1) space complexity. Key insight: Always check if you need to refill before watering the next plant.

What is the brute force solution for Watering Plants?

The brute force approach for Watering Plants is Brute Force, with O(n²) time complexity and O(1) space complexity. The brute force approach simulates each step of watering the plants. We start at the river and move to each plant, checking if we need to refill the watering can after each one. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Watering Plants?

Watering Plants uses the following concepts: Array, Simulation. The recommended patterns to study are: Simulation, Greedy.

What are the interview tips for Watering Plants?

Think aloud while simulating the process to show your thought process. Consider edge cases, such as when all plants can be watered without refilling. Practice writing clean and efficient code to improve your coding speed during interviews.

What are common mistakes when solving Watering Plants?

Not accounting for the return trip to the river after watering the last plant. Failing to reset the water level after refilling.

#2079

Watering Plants

Medium

ArraySimulationSimulationGreedy

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n²)	O(n)
Space	O(1)	O(1)

💡

Intuition

Time O(n)Space O(1)

The optimal approach efficiently tracks the water needed and minimizes unnecessary trips to the river. We only return to refill when necessary, keeping track of the water left in the can.

⚙️

Algorithm

3 steps

1Step 1: Initialize total steps and current water.
2Step 2: Iterate through each plant, updating steps and current water.
3Step 3: If current water is insufficient for the next plant, calculate the steps to return to the river and refill.

solution.py10 lines

1def wateringPlants(plants, capacity):
2    steps = 0
3    current_water = capacity
4    for i in range(len(plants)):
5        if current_water < plants[i]:
6            steps += (i + 1)  # Return to river
7            current_water = capacity
8        steps += 1  # Watering the plant
9        current_water -= plants[i]
10    return steps + len(plants)  # Add steps to return to river after last plant

ℹ

Complexity note: The optimal solution runs in O(n) time because we only traverse the list of plants once, making decisions based on the current water level.

1Always check if you need to refill before watering the next plant.
2Minimize trips to the river by tracking the current water level.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.