LeetCode in Kotlin

2079. Watering Plants

Medium

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 the following way:

• 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.

Example 1:

Input: plants = [2,2,3,3], capacity = 5

Output: 14

Explanation: Start at the river with a full watering can:

• Walk to plant 0 (1 step) and water it. Watering can has 3 units of water.

• Walk to plant 1 (1 step) and water it. Watering can has 1 unit of water.

• Since you cannot completely water plant 2, walk back to the river to refill (2 steps).

• Walk to plant 2 (3 steps) and water it. Watering can has 2 units of water.

• Since you cannot completely water plant 3, walk back to the river to refill (3 steps).

• Walk to plant 3 (4 steps) and water it.

Steps needed = 1 + 1 + 2 + 3 + 3 + 4 = 14.

Example 2:

Input: plants = [1,1,1,4,2,3], capacity = 4

Output: 30

Explanation: Start at the river with a full watering can:

• Water plants 0, 1, and 2 (3 steps). Return to river (3 steps).

• Water plant 3 (4 steps). Return to river (4 steps).

• Water plant 4 (5 steps). Return to river (5 steps).

• Water plant 5 (6 steps).

Steps needed = 3 + 3 + 4 + 4 + 5 + 5 + 6 = 30.

Example 3:

Input: plants = [7,7,7,7,7,7,7], capacity = 8

Output: 49

Explanation: You have to refill before watering each plant.

Steps needed = 1 + 1 + 2 + 2 + 3 + 3 + 4 + 4 + 5 + 5 + 6 + 6 + 7 = 49.

Constraints:

• n == plants.length
• 1 <= n <= 1000
• 1 <= plants[i] <= 106
• max(plants[i]) <= capacity <= 109

Solution

@Suppress("NAME_SHADOWING")
class Solution {
    fun wateringPlants(plants: IntArray, capacity: Int): Int {
        var capacity = capacity
        val initial = capacity
        var ans = 0
        for (i in plants.indices) {
            if (plants[i] <= capacity) {
                ++ans
                capacity -= plants[i]
            } else {
                ans += i
                capacity = initial
                ans += i + 1
                capacity -= plants[i]
            }
        }
        return ans
    }
}

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