Nicholas (nikaj)

Optimizing, AtCoder Heuristic Rank #1, Past: MemSQL(SingleStoreDB)

[Nicholas (nikaj) @nikaitsu]

#AHC072 17th provisional. SA on a DAG of operations. Seed 1:

[Nicholas (nikaj) @nikaitsu]

51 points on seed=0
#AHC072 #visualizer

[Nicholas (nikaj) @nikaitsu]

nikaj took 2nd place in AtCoder Heuristic Contest 071!
Performance: 3155
Rating: 3302→3310 (+8) :)
#AtCoder #AHC071 https://t.co/mXmgPnfwew

[Nicholas (nikaj) @nikaitsu]

#AHC071 | 1,590,489 pts | Top 3 Basic SA: The state represents which bricks of size >1 are added. Size=1 bricks are determined in a single top-to-bottom pass in O(H) using bitmasks. Transitions include adding, removing, replacing, or shifting a single brick.

[Nicholas (nikaj) @nikaitsu]

#AHC070 I could only use two vectors

[Nicholas (nikaj) @nikaitsu]

First time solving an optimization contest without reading the statement

[Nicholas (nikaj) @nikaitsu]

#AHC069 Provisional 9th place

Use acceptance criteria based on the estimated theta, grid occupancy, and score, checked both before and after finding a placement.

In addition to maximizing score, improve the expected availability of adjacent free-cell pairs.

[Nicholas (nikaj) @nikaitsu]

Start candidate regions at random positions and expand them greedily, one cell at a time. When space permits, this produces roughly square regions.

Apply a small hill-climbing afterward.

Consider placements that relocate zero, one, or two groups.