Hello! I am a 24-year-old scholar.
In this round, I solved all problems and the solutions passed system tests, but I failed this Qual.
I got only 2,250 points (150+300+450+600+750) and the 1085th place. -> Standings
I think this round was in intense competition ...
A
In Problem A, we are required to implement carefully. — My solution is O(N log N).
B
In Problem B, we can't use O(N^2) algorithm. — My solution is O(1000^2) with two-dimensional array.
C
Problem C is very nice, but it is difficult for "Problem C".
Getting the improvement for O(nks) is easy, but implementations are slightly complicated for beginners.
--- My solution is O(N log N) with self-balancing binary search tree.
D
In Problem D, we are required to use O(N^2) algorithm for getting palindromic substring. — My solution is O(N^2) with effective palindrome judgment.
E
In Problem E, we are required to notice that "number of use" is important. — My solution is O(N log N) with a lot of sortings.
By the way, I like data structures. Data structures were required by most problems, so I like this round.
You are my hero! I will always remember you before submitting a problem!
P.S. 128 submits are truly great result
P.P.S. My personal best is +33 and I even thought that it's impossible to accomplish any bigger, but your achivement gives me faith.
Not that it matters for you anymore but since you are 24 you weren't even allowed to participate (unless your birthday was a couple of days ago, in that case 'happy belated birthday!').
Problem C may can use simple way with O(n * (k + s)) . Just count every number appear times in every segment(there are k segment), then just like implement. Find the letter you want to delete in which segment , then spend O(s) to find it in the segment. I think it may be work fine with time limited 3s. (Forgive my poor English...)