1580. Put Boxes Into the Warehouse II

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.

class Solution {
public:
    int maxBoxesInWarehouse(vector<int>& boxes, vector<int>& w) {
        int l = 0, r = w.size() - 1;
        while(l + 1 < r) {
            if(w[l] > w[r]) {
                if(w[l] < w[l + 1])
                    w[l + 1] = w[l];
                l++;
            } else {
                if(w[r] < w[r - 1])
                    w[r - 1] = w[r];
                r--;
            }
        }
        sort(boxes.begin(), boxes.end());
        int res = 0;
        while(res < boxes.size() and (0 <= l or r < w.size())) {
            if(0 <= l and r < w.size()) {
                if(w[l] >= boxes[res] and w[r] >= boxes[res]) {
                    if(w[l] < w[r])
                        l--;
                    else r++;
                    res++;
                } else if(w[l] >= boxes[res]) {
                    r++;
                } else {
                    l--;
                }
            } else if(0 <= l) {
                if(w[l] >= boxes[res])
                    res++;
                l--;
            } else {
                if(w[r] >= boxes[res])
                    res++;
                r++;
            }
        }
        return res;
    }
};