Package g3601_3700.s3679_minimum_discards_to_balance_inventory

Class Solution

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public final class Solution

    3679 - Minimum Discards to Balance Inventory.

    Medium

    You are given two integers w and m, and an integer array arrivals, where arrivals[i] is the type of item arriving on day i (days are 1-indexed ).

    Items are managed according to the following rules:

    • Each arrival may be kept or discarded; an item may only be discarded on its arrival day.

    • For each day i, consider the window of days [max(1, i - w + 1), i] (the w most recent days up to day i):

    Return the minimum number of arrivals to be discarded so that every w\-day window contains at most m occurrences of each type.

    Example 1:

    Input: arrivals = 1,2,1,3,1, w = 4, m = 2

    Output: 0

    Explanation:

    • On day 1, Item 1 arrives; the window contains no more than m occurrences of this type, so we keep it.

    • On day 2, Item 2 arrives; the window of days 1 - 2 is fine.

    • On day 3, Item 1 arrives, window [1, 2, 1] has item 1 twice, within limit.

    • On day 4, Item 3 arrives, window [1, 2, 1, 3] has item 1 twice, allowed.

    • On day 5, Item 1 arrives, window [2, 1, 3, 1] has item 1 twice, still valid.

    There are no discarded items, so return 0.

    Example 2:

    Input: arrivals = 1,2,3,3,3,4, w = 3, m = 2

    Output: 1

    Explanation:

    • On day 1, Item 1 arrives. We keep it.

    • On day 2, Item 2 arrives, window [1, 2] is fine.

    • On day 3, Item 3 arrives, window [1, 2, 3] has item 3 once.

    • On day 4, Item 3 arrives, window [2, 3, 3] has item 3 twice, allowed.

    • On day 5, Item 3 arrives, window [3, 3, 3] has item 3 three times, exceeds limit, so the arrival must be discarded.

    • On day 6, Item 4 arrives, window [3, 4] is fine.

    Item 3 on day 5 is discarded, and this is the minimum number of arrivals to discard, so return 1.

    Constraints:

    • <code>1 <= arrivals.length <= 10<sup>5</sup></code>

    • <code>1 <= arrivalsi<= 10<sup>5</sup></code>

    • 1 &lt;= w &lt;= arrivals.length

    • 1 &lt;= m &lt;= w

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer minArrivalsToDiscard(IntArray arrivals, Integer w, Integer m)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait