April (US Open) 2014 Silver Problem 2: Dueling GPSs

Result: incomplete

I've never implemented Dijkstra's algorithm before, and I couldn't do it in time.

gpsduel.cpp

April (US Open) 2014 Silver Problem 1: Fair Photography

Result: 6/10 *****t*ttt

I'm not sure how to implement this faster.

fairphoto.cpp

March 2014 Silver Problem 3: Mooo Moo

Result: incomplete

I gave up, and the partial code in this file is pointless.

mooomoo.cpp

March 2014 Silver Problem 2: The Lazy Cow

Result: 5/10 *****ttttt

Silver is significantly more difficult than bronze.

lazy.cpp

February 2014 Bronze Problem 3: Secret Code

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

This one took more time than Problem 1 and Problem 2, but at least I actually finished this Problem 3, unlike the last few ones.

scode.cpp

February 2014 Bronze Problem 2: Auto-complete

Result: 7/10 *****tt**t

Just sort the entries, but also store the original position, then process the requests.

auto.cpp

February 2014 Bronze Problem 1: Mirror Field

Result: 8/10 **x*x*****

This is actually more difficult than Problem 2, which I completed first.

mirror.cpp

January 2014 Bronze Problem 3: Balanced Teams

Result: (incomplete)

It's too difficult, so I give up.

bteams.cpp

January 2014 Bronze Problem 2: Bessie Slows Down

Result: 1/10 *xxxxxxxxx

My solution is O(N log N), but I somehow made an error somewhere (probably rounding errors).

slowdown.cpp

January 2014 Bronze Problem 1: Ski Course Design

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

My solution is O(N^2), but up to 83*99 iterations.

skidesign.cpp

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

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

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

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