Search found 63 matches

by roticv
Fri Jun 18, 2010 3:35 pm
Forum: Bugs and suggestions
Topic: My statistics
Replies: 1
Views: 1274

Re: My statistics

Now it is back to normal.
by roticv
Fri Jun 18, 2010 11:15 am
Forum: Bugs and suggestions
Topic: My statistics
Replies: 1
Views: 1274

My statistics

Hello,

I have solved 961 problems as of yesterday. However, when I logged in today, I found out that my number of problems solved became 2 and number of total submissions became 2. What happened to my account??!

PS My user number is 8764.
by roticv
Wed Jun 16, 2010 5:41 pm
Forum: Volume 111 (11100-11199)
Topic: 11196 - Birthday Cake
Replies: 2
Views: 4512

Re: 11196 - Birthday Cake

Thank for the hint. Managed to solved it after so long.

A hint from me is that the order you search matters too. I just changed the order and my code which probably takes hours to run manage to solve the largest test case in a short time.
by roticv
Tue Jul 28, 2009 5:45 am
Forum: Volume 111 (11100-11199)
Topic: 11155 - Be Efficient
Replies: 15
Views: 10405

Re: 11155 - Be Efficient

There's an O(n) solution. Almost similar in idea to 11237
by roticv
Fri Jul 17, 2009 9:27 am
Forum: Volume 113 (11300-11399)
Topic: 11311 - Exclusively Edible
Replies: 5
Views: 5395

Re: 11311 - Exclusively Editable

Think nim/nim sum.
by roticv
Thu Jul 02, 2009 9:20 am
Forum: Volume 114 (11400-11499)
Topic: 11404 - Palindromic Subsequence
Replies: 25
Views: 13884

Re: 11404 - Palindromic Subsequence

You are using the wrong method. It does not give you the smallest lexicographical palindrome.
by roticv
Thu Jul 02, 2009 9:15 am
Forum: Volume 113 (11300-11399)
Topic: 11338 - Minefield
Replies: 10
Views: 3894

Re: 11338 - Minefield

Inserting into a map takes O(lg n) and hence you got TLE.

Using O(n^2) algorithm to generate all the edges result in my code taking 0.7+s. I think using kd-tree will result in faster runtime.
by roticv
Sat Jun 13, 2009 9:34 am
Forum: Bugs and suggestions
Topic: Special Corrector Problem - Always PE
Replies: 10
Views: 4882

Re: Special Corrector Problem - Always PE

I'm encountering the same problem too...
by roticv
Fri Jun 12, 2009 5:28 am
Forum: Volume 100 (10000-10099)
Topic: 10090 - Marbles
Replies: 43
Views: 22308

Re: 10090 - Marbles

use %lld
by roticv
Tue Jun 09, 2009 10:18 am
Forum: Volume 115 (11500-11599)
Topic: 11525 - Permutation
Replies: 9
Views: 3323

Re: 11525 - Permutation

There is no need to compute factorials. Just find the kth smallest number that is not used (k starts from 0...so-on).

People have suggested using interval/segment trees to solve this problem. I've used fenwick trees to solve it. It is possible to find the kth smallest number using binary search.
by roticv
Mon Jun 01, 2009 10:26 am
Forum: Volume 4 (400-499)
Topic: 437 - The Tower of Babylon
Replies: 14
Views: 7964

Re: 437 - Any good idea for Towers of Babylonia?

I finally realised that there is a linear solution to the problem - solving longest path on a DAG.
by roticv
Mon Jun 01, 2009 7:39 am
Forum: Volume 115 (11500-11599)
Topic: 11596 - Convex Orthogonal Polygon
Replies: 2
Views: 1460

Re: 11596 - Convex Orthogonal Polygon

You are moving towards the right direction.

If you really want a hint take a look at Steven Halim's website (a solution by Minh Duc): http://www.comp.nus.edu.sg/~stevenha/pr ... al_Polygon
by roticv
Sun May 31, 2009 8:53 am
Forum: Volume 114 (11400-11499)
Topic: 11475 - Extend to Palindrome
Replies: 32
Views: 13887

Re: 11475 - Extend to Palindromes

Well let me drop one hint.

In this problem we have to find the suffix of the string that is the longest palindrome. This problem can be solved using a slightly modified KMP with the search string the reverse of the original string.

Therefore, this problem can be solved in linear time.
by roticv
Thu May 28, 2009 4:48 am
Forum: Volume 116 (11600-11699)
Topic: 11610 - Reverse Prime
Replies: 7
Views: 3257

Re: 11610 - Reverse Prime

You didn't comment out your freopen. I think your code might TLE.
by roticv
Tue May 26, 2009 4:50 pm
Forum: Volume 114 (11400-11499)
Topic: 11440 - Help Tomisu
Replies: 9
Views: 3402

Re: 11440 - Help Tomisu

phi(N!) = number of numbers between 1 and N! which has no common factors with (1...N) ie number of numbers between 1 and N! with prime factors > N.

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