luogu#P2894. [USACO08FEB] Hotel G

[USACO08FEB] Hotel G

Problem Description

The cows are journeying north to Thunder Bay in Canada to gain cultural enrichment and enjoy a vacation on the sunny shores of Lake Superior. Bessie, ever the competent travel agent, has named the Bullmoose Hotel on famed Cumberland Street as their vacation residence. This immense hotel has NN (1N50,0001 \le N \le 50,000) rooms all located on the same side of an extremely long hallway (all the better to see the lake, of course).

The cows and other visitors arrive in groups of size DiD_i (1DiN1 \le D_i \le N) and approach the front desk to check in. Each group ii requests a set of DiD_i contiguous rooms from Canmuu, the moose staffing the counter. He assigns them some set of consecutive room numbers rr+Di1r \cdots r + D_i - 1 if they are available or, if no contiguous set of rooms is available, politely suggests alternate lodging. Canmuu always chooses the value of r to be the smallest possible.

Visitors also depart the hotel from groups of contiguous rooms. Checkout ii has the parameters XiX_i and DiD_i which specify the vacating of rooms XiXi+Di1X_i \cdots X_i + D_i - 1 (1XiNDi+11 \le X_i \le N - D_i + 1). Some (or all) of those rooms might be empty before the checkout.

Your job is to assist Canmuu by processing MM (1M50,0001 \le M \le 50,000) checkin/checkout requests. The hotel is initially unoccupied.

Input Format

  • Line 11: Two space-separated integers: NN and MM

  • Lines 2M+12 \cdots M + 1: Line i+1i + 1 contains request expressed as one of two possible formats: (a) Two space separated integers representing a check-in request: 11 and DiD_i (b) Three space-separated integers representing a check-out: 22, XiX_i, and DiD_i

Output Format

  • Lines 11 \cdots: For each check-in request, output a single line with a single integer rr, the first room in the contiguous sequence of rooms to be occupied. If the request cannot be satisfied, output 00.
10 6
1 3
1 3
1 3
1 3
2 5 5
1 6

1
4
7
0
5