Put Boxes Into the Warehouse II(LeetCode 1580):

Problem

You are given two arrays of positive integers, boxes and warehouse, representing the heights of some boxes of unit width and the heights of n rooms in a warehouse respectively. The warehouse's rooms are labeled from 0 to n - 1 from left to right where warehouse[i] (0-indexed) is the height of the ith room.

Boxes are put into the warehouse by the following rules:

  • Boxes cannot be stacked.
  • You can rearrange the insertion order of the boxes.
  • Boxes can be pushed into the warehouse from either side (left or right)
  • If the height of some room in the warehouse is less than the height of a box, then that box and all other boxes behind it will be stopped before that room.

Return the maximum number of boxes you can put into the warehouse.

 

Example 1:

Input: boxes = [1,2,2,3,4], warehouse = [3,4,1,2]
Output: 4
Explanation:

We can store the boxes in the following order:
1- Put the yellow box in room 2 from either the left or right side.
2- Put the orange box in room 3 from the right side.
3- Put the green box in room 1 from the left side.
4- Put the red box in room 0 from the left side.
Notice that there are other valid ways to put 4 boxes such as swapping the red and green boxes or the red and orange boxes.

Example 2:

Input: boxes = [3,5,5,2], warehouse = [2,1,3,4,5]
Output: 3
Explanation:

It is not possible to put the two boxes of height 5 in the warehouse since there's only 1 room of height >= 5.
Other valid solutions are to put the green box in room 2 or to put the orange box first in room 2 before putting the green and red boxes.

 

Constraints:

  • n == warehouse.length
  • 1 <= boxes.length, warehouse.length <= 105
  • 1 <= boxes[i], warehouse[i] <= 109