E869120's blog

By E869120, history, 7 months ago, ,

Dear Codeforces community.

AtCoder Beginner Contest 106 will be held at Saturday, August 18th, 21:00 JST.

Here is some contest informations:

• The contest is rated for participants whose rating is 1199 or lower.
• The writers are: E869120 and square1001. We are 16-years-old twin brothers :)
• Duration is 100 minutes.
• There are 4 tasks in this contest.

Let's participate and enjoy for this contest, and discuss the problems after the contest.
Good luck and have fun!
---
E869120, square1001

UPDATE
The contest is over, and editorial is out!

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 » 7 months ago, # |   +8 I have a reminder. The contest will start in ... 2 hours!
 » 7 months ago, # |   +6 Why Atcoder doesn't have regular contests like codeforces ?
•  » » 7 months ago, # ^ |   0 Also, the ratings from previous AtCoder Beginner contest-105 have not been updated till now.
•  » » » 7 months ago, # ^ |   +8 ABC 105 was unrated, because of organizer's mistake. I hope that this contest is not unrated.
•  » » » » 7 months ago, # ^ |   0 Oh sorry, I was not aware of that.
 » 7 months ago, # |   0 Can you make this an Announcement and Discussion Page so that we can discuss here only? ThanksAlso, After the contest is over, can someone please give the solution of D? I am trying but I don't think I will be able to solve it in the given time frame.
 » 7 months ago, # |   +3 nice problems.D was pretty awesome.
 » 7 months ago, # |   0 How to solve C and D ?
•  » » 7 months ago, # ^ |   0 i understand how to solve C ,it was my stupid mistake . Please help with D
•  » » » 7 months ago, # ^ |   0 For the problem D I use a BIT to find the amount of numbers less than R and I sorted the queries to decrease the values of the BIT.
•  » » » 7 months ago, # ^ | ← Rev. 2 →   0 #include using namespace std; typedef long long ll; typedef unsigned long long ull; typedef pair PII; typedef pair PLL; typedef double ld; #define pb push_back #define all(c) c.begin(),c.end() #define allr(c) c.rbegin(),c.rend() #define MOD 1000000007 #define PI 3.14159265 #define MAX 501 vector vec[MAX]; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int n , m , q; cin >> n >> m >> q; int l , r; for (int i = 0; i < m; i++) { cin >> l >> r; vec[l].pb(r); } for (int i = 1; i <= n; i++) { sort(all(vec[i])); } int ans = 0; for (int i = 0; i < q; i++) { cin >> l >> r; ans = 0; for (int j = l; j <= r; j++) { int ind = lower_bound(all(vec[j]) , r + 1) - vec[j].begin(); ans += (ind); } cout << ans << endl; } return 0; } 
•  » » » » 7 months ago, # ^ | ← Rev. 2 →   0 i like this idea,thanks starboy_jb !
•  » » » » » 7 months ago, # ^ |   0 welcome bro.
 » 7 months ago, # |   0 Auto comment: topic has been updated by E869120 (previous revision, new revision, compare).
 » 7 months ago, # |   +9 Editorial is out! link
•  » » 7 months ago, # ^ | ← Rev. 2 →   +9 Thanks for providing it in English too.
•  » » 7 months ago, # ^ |   0 Just a question out of curiosity, if the range of N was something 1 ≤ N ≤ 105. Can you suggest some optimize approach for this? As the current solution will easily timeout.
 » 7 months ago, # |   0 It was my first contest at AtCoder and I'm extremely disappointed with it — in particular, with the difficulty of the tasks. Of course, nobody expects Div1 difficulty from Div2 tasks but isn't it ridiculous that 4 tasks are easily solvable within 30 minutes in a contest which is supposed to last 100 minutes?
•  » » 7 months ago, # ^ |   +38 Do you know that it is AtCoder "Beginner" Contest? It is much easier than, say, Topcoder Div2, or Codeforces Div3. Implying that it is rated for rating <=1200, it implies that it is very fitting for people like Topcoder rating <= 1100, or Codeforces rating <= 1400. There are AtCoder Regular Contest and AtCoder Grand Contest, which is much harder one. If you feel like it is easy, you are pro coder and you are expected to participate in ARC or AGC. Let's see the standings again — problem D is only solved for quarter of participants. It means you are definitely top 25% coder. Have confidence!
•  » » » 7 months ago, # ^ |   0 The problem is that other types of contests don't happen often — last four contests were for "Beginners".
•  » » » » 7 months ago, # ^ |   -19 today is the third contest in a row on CF. It isn't enough?
•  » » » » » 7 months ago, # ^ |   +3 We're talking about AtCoder contests here :)
•  » » » » » » 7 months ago, # ^ |   0 this aycoder contest was more like codeforces div.4
•  » » » 7 months ago, # ^ |   0 I expected at least problem D to be challenging but,compared to previous beginner contests,I felt that problem D was way too easier this time.
 » 7 months ago, # |   +8 Dear friends, Here is my editorial on Problem D. It is quite different from the editorial solution. :)