### Gol_D's blog

By Gol_D, history, 2 years ago,

1660A - Vasya and Coins

Idea: MikeMirzayanov

Tutorial
Solution

Tutorial
Solution

1660C - Get an Even String

Idea: MikeMirzayanov

Tutorial
Solution

1660D - Maximum Product Strikes Back

Idea: Aris

Tutorial
Solution

1660E - Matrix and Shifts

Idea: myav, MikeMirzayanov

Tutorial
Solution

1660F1 - Promising String (easy version)

Idea: MikeMirzayanov

Tutorial
Solution

1660F2 - Promising String (hard version)

Idea: MikeMirzayanov

Tutorial
Solution
• +50

| Write comment?
 » 2 years ago, # |   +6 If you are/were getting a WA/RE verdict on problems from this contest, you can get the smallest possible counter example for your submission on cfstress.com. To do that, click on the relevant problem's link below, add your submission ID, and edit the table to increase/decrease the constraints.I've also added a new feature to view progress of your judgement in near real-time. (For example, the current state of your ticket, how many inputs were evaluated, etc). If you are not able to find a counter example even after changing the parameters, reply to this thread, mentioning the contest_id, problem_index and submission_id.
 » 2 years ago, # |   +4 my divide and conquer solution for fhttps://mirror.codeforces.com/contest/1660/submission/152497191
•  » » 2 years ago, # ^ |   0 Can you explain ur solution
•  » » » 2 years ago, # ^ |   0 in problem I made simple observation that whenever number of negative is greaterlet say r = number of negative in subarray — number of pos in subarrayif r >0 and r%3 == 0 then subarray will be promissing I used divide and conquer to calculate those subarray
 » 2 years ago, # | ← Rev. 2 →   +6 There is a solution in the f2 order_set or fenw_tree.This is awesome
 » 2 years ago, # |   0 Can anyone please point out for me the difference between these two submissions:152864441(I used vector and got WA)152864364 (I used array and got AC)Thanks in advance!!!
•  » » 2 years ago, # ^ |   0 Most likely this is due to integer overflow with arrays.
•  » » » 2 years ago, # ^ |   0 Can you elaborate more for me ? I'm still confused. Thank you very much!
•  » » » » 2 years ago, # ^ | ← Rev. 3 →   0 Look at expression in line 21:if((n == 1 && vec[0] > 1) || (vec[n — 1] — vec[n — 2] > 1))The condition behind the OR doesn't check for vector size, so for n == 1, then you are evaluating this: (vec[0] — vec[-1] > 1)Imagine this input:111Then:(n == 1 && vec[0] > 1) || (vec[0] — vec[-1] > 1)(1 == 1 && 1 > 1) || (1 — vec[-1] > 1)(true && false) || (1 — vec[-1] > 1)false || (1 — ?? > 1)So basically you are accessing vec[-1]. Depending on the value in that "illegal" memory position, it may be true or false. Same happens for arr[-1], but you just go lucky there with the memory value there at the time of the submit.
•  » » » » » 2 years ago, # ^ |   0 Wow, now I get that! Thanks very much!
 » 2 years ago, # | ← Rev. 2 →   0 Does the solution of F1 take into account the adjacent situation?
 » 2 years ago, # |   0 How can I solve C. Get an Even String with dp ?
 » 22 months ago, # | ← Rev. 2 →   0 I think there is a mistake in tutorial for problem C. Instead of used it should be prev.
 » 9 months ago, # |   0 import java.util.*; public class A_Vasya_and_Coins { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int t = sc.nextInt(); while(t-->0) { int a = sc.nextInt(); int b = sc.nextInt(); int a1 = a*1; int a2 = b*2; if(a==0) System.out.println(1); else { int ans = (a1+a2) + 1; System.out.println(ans); } } } } nice
 » 7 weeks ago, # |   0 Can someone give me the DP solution of number C? I think it will help me get intuition faster to this types of problems.
 » 4 weeks ago, # | ← Rev. 2 →   0 Can anyone give counter test case for my solution for D here it is:257423322 getting wrong ans on test 2