1564. Put Boxes Into the Warehouse I

https://leetcode.com/problems/put-boxes-into-the-warehouse-i

Description

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 labelled 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 only be pushed into the warehouse from left to right only.

• 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 = [4,3,4,1], warehouse = [5,3,3,4,1]
**Output:** 3
**Explanation:**![](https://assets.leetcode.com/uploads/2020/08/26/12.png)
We can first put the box of height 1 in room 4. Then we can put the box of height 3 in either of the 3 rooms 1, 2, or 3. Lastly, we can put one box of height 4 in room 0.
There is no way we can fit all 4 boxes in the warehouse.

Example 2:

**Input:** boxes = [1,2,2,3,4], warehouse = [3,4,1,2]
**Output:** 3
**Explanation: 
![](https://assets.leetcode.com/uploads/2020/08/26/22.png)**Notice that it's not possible to put the box of height 4 into the warehouse since it cannot pass the first room of height 3.
Also, for the last two rooms, 2 and 3, only boxes of height 1 can fit.
We can fit 3 boxes maximum as shown above. The yellow box can also be put in room 2 instead.
Swapping the orange and green boxes is also valid, or swapping one of them with the red box.

Example 3:

**Input:** boxes = [1,2,3], warehouse = [1,2,3,4]
**Output:** 1
**Explanation:** Since the first room in the warehouse is of height 1, we can only put boxes of height 1.

Example 4:

**Input:** boxes = [4,5,6], warehouse = [3,3,3,3,3]
**Output:** 0

Constraints:

• n == warehouse.length

• 1 <= boxes.length, warehouse.length <= 10^5

• 1 <= boxes[i], warehouse[i] <= 10^9

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