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2105. Watering Plants II

  • Time: $O(n)$
  • Space: $O(1)$
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class Solution {
 public:
  int minimumRefill(vector<int>& plants, int capacityA, int capacityB) {
    int ans = 0;
    int i = 0;
    int j = plants.size() - 1;
    int canA = capacityA;
    int canB = capacityB;

    while (i < j) {
      ans += (canA < plants[i]) + (canB < plants[j]);
      if (canA < plants[i])
        canA = capacityA;
      if (canB < plants[j])
        canB = capacityB;
      canA -= plants[i++];
      canB -= plants[j--];
    }

    return ans + (i == j && max(canA, canB) < plants[i]);
  }
};

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class Solution {
  public int minimumRefill(int[] plants, int capacityA, int capacityB) {
    int ans = 0;
    int i = 0;
    int j = plants.length - 1;
    int canA = capacityA;
    int canB = capacityB;

    while (i < j) {
      ans += (canA < plants[i] ? 1 : 0) + (canB < plants[j] ? 1 : 0);
      if (canA < plants[i])
        canA = capacityA;
      if (canB < plants[j])
        canB = capacityB;
      canA -= plants[i++];
      canB -= plants[j--];
    }

    return ans + (i == j && Math.max(canA, canB) < plants[i] ? 1 : 0);
  }
}

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class Solution:
  def minimumRefill(
      self,
      plants: list[int],
      capacityA: int,
      capacityB: int,
  ) -> int:
    ans = 0
    i = 0
    j = len(plants) - 1
    canA = capacityA
    canB = capacityB

    while i < j:
      ans += (canA < plants[i]) + (canB < plants[j])
      if canA < plants[i]:
        canA = capacityA
      if canB < plants[j]:
        canB = capacityB
      canA -= plants[i]
      canB -= plants[j]
      i += 1
      j -= 1

    return ans + (i == j and max(canA, canB) < plants[i])