3074. Apple Redistribution into Boxes

Time: O(n log C)

Space: O(1)

Approach

Binary search on box capacity; validate smallest boxes can hold all grouped apples.

Key Techniques

Array problems involve manipulating elements stored in a contiguous block of memory. Key techniques include two-pointer traversal, prefix sums, sliding windows, and in-place partitioning. In C#, arrays are zero-indexed and fixed in size — use List<T> when you need dynamic resizing.

Greedy

Greedy algorithms make locally optimal choices at each step, hoping to reach a global optimum. Greedy works when a problem has the "greedy choice property" and "optimal substructure". Common applications: interval scheduling, activity selection, Huffman coding, and jump game.

3074.cs

// Approach: Binary search on box capacity; validate smallest boxes can hold all grouped apples.
// Time: O(n log C) Space: O(1)

public class Solution
{
    public int MinimumBoxes(int[] apple, int[] capacity)
    {
        int appleSum = apple.Sum();
        int capacitySum = 0;

        Array.Sort(capacity);

        for (int i = 0; i < capacity.Length; ++i)
        {
            capacitySum += capacity[capacity.Length - 1 - i];
            if (capacitySum >= appleSum)
                return i + 1;
        }

        return capacity.Length;
    }
}

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