Sphere Online Judge

SPOJ Problem Set (classical)

5977. Weird Function

Problem code: WEIRDFN

Let us define :
F[1] = 1
F[i] = (a*M[i] + b*i + c)%1000000007 for i > 1

where M[i] is the median of the array {F[1],F[2],..,F[i-1]}.
The median of an array is the middle element of that array when it is sorted. If there are an even number of elements in the array, we choose the first of the middle two elements to be the median.

Given a,b,c and n, calculate the sum F[1] + F[2] + .. + F[n].


The first line contains T the number of test cases. Each of the next T lines contain 4 integers : a,b,c and n.


Output T lines, one for each test case, containing the required sum.


Sample Input :
1 0 0 3
3 1 2 6

Sample Output :


1 <= T <= 100
0 <= a,b,c < 1000000007
1 <= n <= 200000

Added by:Varun Jalan
Time limit:6s
Source limit:50000B
Memory limit:256MB
Cluster: Pyramid (Intel Pentium III 733 MHz)
Languages:All except: NODEJS PERL 6
Resource:own problem used for Codechef Snackdown Onsite

hide comments
2014-09-13 15:53:45 Kunal Behl
y time limit exceed everytime?? can anybody help please..
2014-06-04 21:24:16 Matija MartiniŠ
TLE even after using stl heap c++... :(
what to do now..??
2014-04-23 19:14:51 sam17121991
oh my gosh!
2014-02-02 23:17:12 (Tjandra Satria Gunawan)(曾毅昆)
Time limit is too strict!
2013-05-17 12:42:45 SaSukE
why implementation using red black tree is giving TLE ?? :/....Insertion and every query takes O(logn) still getting TLE ?? What should be the complexity of the solutn ??

Last edit: 2013-05-17 12:56:55
2013-02-03 13:36:52 J.A.R.V.I.S.
Nice one :) solvable with STLs.. Watch out for overflows...
2013-01-27 12:20:48 conioh
nice question...
2012-12-09 20:07:18 Nilendu Das
Good question.. You can take help from RRATING problem from codechef..Jst the partition is diff..
2012-11-19 06:26:53 Paul Draper
This problems "allows" for languages other than C/C++, but the time limit does not.
2012-08-15 03:19:05 Anand
Very nice problem I am getting TLE
© Spoj.com. All Rights Reserved. Spoj uses Sphere Engine™ © by Sphere Research Labs.