We will hold AtCoder Beginner Contest 449.
- Contest URL: https://atcoder.jp/contests/abc449
- Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20260314T2100&p1=248
- Duration: 100 minutes
- Writer: sounansya, cn449, toam
- Tester: harurun4635, KumaTachiRen
- Rated range: ~ 1999
- The point values: 100-200-300-425-475-500-600
We are looking forward to your participation!
GOOD!!!
Good luck!
This is my first contest
I hope this will be a good one, as every ABC is.
This is my second contest,0I'm such a waste!
Good!
what is a TLE?
It is the short form of "Time Limit Exceed", where your code exceed the limit time for the problem. For instance, a problem could have a limit time of 2000ms, and if your code do 1000000000 (Or 10^9) operations (Or O(1e9)), you will receive a TLE
Time Limit Exceeded,your code's efficiency is not enough.
Yes! Good luck!
D was nice,very great problem which looked scary at first
To me it felt like bunch of case work. Can you share your method?
F's too hard for me to solve..So do you know how to solve?I can't grateful more thx.
I wasted most of the time implementing d, that I couldn't see other problems
i did this
for each x from L,R
if x is odd then find number y's such that y is even and abs(y)>abs(x) and add to result.
if x is even then find number of y's such that abs(y)<abs(x) and find number y's such that y is even and abs(y)>abs(x) (this was used in odd part itself) and add this both of them to result.
my code: https://atcoder.jp/contests/abc449/submissions/74125613
Solved $$$E$$$ in 10 minutes, couldn't solve $$$D$$$ even after 50 minutes :(
The second worst round I have ever participated in. Not fun and coding is suffering.
To solve D and E you just need to implement your code and fix thousands of little bugs rather than design a excellent algorithm.
BTW the worst round is ABC421 whose problem D is "RLE Moving".
D FK FKFKFKFKFKFKFKFK It take me more than 70 minutes F is hard ,E is fk this contest take me rated
from 1201 to 1190
Was C a sliding window?
Yes
I hate C
no its just prefix sums think about it
You can implement it using sliding window and a map, but I did it by mentaining the frequency array of a-z, which is probably slower, and won't work if the problem had used a array instead of string,
i did lower and upper bound on array of indices of each characters
You can just maintain a prefix sum array for every character from 'a' to 'z'.
And for every character s[i] of the string s, calculate the interval sum of s[i] from $$$i - r$$$ to $$$i - l$$$ (inclusive) and add up to your answer.
Also, you can use binary search.
C其实可以不用滑动窗口
Bro don't say chinese in Codeforces
hi, how do u find the testcases for atcoder contest?
my https://atcoder.jp/contests/abc449/submissions/74124359 this solution failed few testcases and i wanna see which cases it failed
thanks
you cannot find atcoder testcases, they don't release the tcs
I solved F with a slight different approach.
Solution: https://atcoder.jp/contests/abc449/submissions/74103781
does atcoder have good problems? i have been considering doing atcoder for a while now because of their schedule
Can someone explain problem E please? I am having a hard time understanding the editorial.
Today's E and F are somehow implementation-heavy. But the involved ideas are good to learn I think.
Problem E needs "online to offline", "find k-th small element based on segment tree". Problem F needs "sweep-line-similar-idea", "use set to update some value with element adding and removing".