Tuesday, December 17, 2013

December 2013 Bronze Problem 3: Wormholes

Result: incomplete

It's too difficult, but I had it partially done. Other partial work is in the recycling by now.

wormhole.cpp

December 2013 Bronze Problem 2: Cow Baseball

Result: 1/10 *xxxxxxxxx

N2 log N time might be too slow.

baseball.cpp

December 2013 Bronze Problem 1: Record Keeping

Result: 10/10 **********

As long as there aren't any hash collisions, this is a fast solution.

records.cpp

Saturday, November 23, 2013

November 2013 Bronze (Correction 2) Problem 1: Combination Lock

Result: 10/10 **********

This is more optimized than my previous correction though still in O(1) time.

combo2.cpp

November 2013 Bronze (Correction) Problem 1: Combination Lock

Result: 10/10 **********

Upon review, I beat the solution! Though N is no larger than 100, my solution runs in O(1) time and theirs runs in O(N^3) time.

combo2.cpp

Tuesday, November 19, 2013

November 2013 Bronze Problem 3: Farmer John has no Large Brown Cow

Result: 3/10 **ssx*ssss

I somehow ran out of memory and the permutations were not correct in one case.

nocow.cpp

November 2013 Bronze Problem 2: Goldilocks and the N Cows

Result: 7/10 *******ttt

I think that testing every boundary line might be slow, but it's the only way I can think of that does it completely.

milktemp.cpp

November 2013 Bronze Problem 1: Combination Lock

Result: 4/10 *x*xxxx**x

I optimized it near the end, but then I realized that the overlap() function fails when N < 5.

combo.cpp

Tuesday, February 12, 2013

February 2013 Bronze Problem 3: Perimeter

Result: 1/10 *xxxxxxxxx

I found out that this solution is flawed because it doesn't "fill the holes" correctly. It fails when there are two adjacent hole cells.

perimeter.cpp

February 2013 Bronze Problem 2: Cow Crossings

Result: 2/15 *xx*xxxxxxttttt

I realized that I have made a mistake by not checking subsequent cows against cows that have already collided. Example: Cow 1 collides with Cow 2, so they are both marked as collided. Cow 3 will not be checked against Cow 2.

crossings.cpp

February 2013 Bronze Problem 1: Message Relay

Result: 10/10 **********

relay.cpp

Saturday, February 9, 2013

USACO February 2013 Bronze

I forgot about the January contest, so it's too bad that I missed it.

February's contest is easier than November and December's contest, even though this one is 4 hours long. I only needed 1 hour to finish all 3.