Leetcode problem 47 - Watering Plants

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.

/**
 * @param {number[]} plants
 * @param {number} capacity
 * @return {number}
 */
var wateringPlants = function (plants, capacity) {
  let steps = 0;
  let initCapacity = capacity;

  for (let i = 0; i < plants.length; i++) {
    if (capacity >= plants[i]) {
      steps++;
      capacity -= plants[i];
    } else if (capacity < plants[i]) {
      steps += i + i + 1;
      capacity = initCapacity - plants[i];
    }
  }
  return steps;
};

An array plants representing water requirements for plants at different positions and capacity representing the watering can’s capacity. It calculates the minimum number of steps needed to water all plants efficiently. It initializes variables for steps and the initial watering can capacity. Then, it iterates through the plants array, checking if the current plant can be fully watered without refilling the can or if a refill is needed. In the former case, it increments the steps and updates the can’s capacity; in the latter, it increases steps to account for refilling and watering. This process continues for all plants, resulting in the minimum steps required to water them all while considering the watering can’s capacity.