Optimizing, AtCoder Heuristic Rank #1, Past: MemSQL(SingleStoreDB)
Joined June 2012
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#mech_39Contest001 Initial greedy chooses high d cells without creating neighbours. SA transitions were mostly random swaps but then I noticed that diagonal adjacency is beneficial and added it.
Had early cutoff over samples with THRESHOLD=5 parameter. If I set this parameter to 0, I get score 187,196,990 which would be 2nd place.
#mech_39Contest001 Nice problem. Simple SA but didn't have time for parameter tuning.
nikaj took 2nd place in AtCoder Heuristic Contest 071!
Performance: 3155
Rating: 3302→3310 (+8) :)
#AtCoder #AHC071 atcoder.jp/users/nikaj/histo…
#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.
#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.
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.