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POWPOW2 - Power with Combinatorics(HARD) |
Your task is to calculate abexp.
- a: provided in input, 0 ≤ a ≤ 105
- b: provided in input, 0 ≤ b ≤ 105
- exp = (nC0)2 + (nC1)2 + (nC2)2 + ... +(nCn)2
- n: provided in input, 0 ≤ n ≤ 105
Note: The output for 00 should be 1.
nCr denotes n choose r.
As the answer can be too large, you need to output modulo 109+7.
Input
The first line of each input file contains number of test cases t (t ≤ 1000).
Then follows a new line.
Then follows t lines, each containing 3 integers, (i.e. a b n in order) each of them separated by a space.
Output
Output contains t lines, ith line contains the answer of the ith test case.
Example
Input: 1 1 1 1 Output: 1
Explanation
In the first test case, the Value of exp is 2, value of 112 is 1, so output is 1.
Note: First try out the tutorial version where limits are low. POWRTU
Click here to see my set of problems at SPOJ.
Added by: | devu |
Date: | 2012-07-14 |
Time limit: | 0.100s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | Utkarsh Lath |
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2013-09-04 04:43:08 Francky
I did my best and it seems that a Python solution is not possible or ultra hard. I think it would be fine to allow python solution with a little more time, it would still reject bad complexity / fast language solutions. IMHO. |
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2013-09-04 04:43:08 (Tjandra Satria Gunawan)(曾毅昆)
Nice problem! Need a lot of thinks and optimizations to solve it. But my program getting WA... Can you tell me which case that cause my program wrong (ID: 7325908)? Input: 1 79981 79981 79981 Output: 79981 is this correct? Re:It is Correct. Edit: Then why my program wrong? I don't know which case that cause my program wrong. Can you tell me one case that cause my program wrong? Re:I am Srry, i cant tell u any case which might lead to wa,bt as far as tricky cases ,check for 0^0 condition ,if it gives wa again,then rethink ur logic Edit: Thanks for your reply. Now I'm finding for a case that cause my program wrong. My pow() function already correct for 0^0=1 Edit: Thanks for your hint :) Although I still getting WA (After handling tricky test cases)... Last edit: 2012-07-16 20:10:25 |
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2013-09-04 04:43:08 Mitch Schwartz
Interesting, while debugging I found an error (although easily corrected) in a published paper. I can't be more specific without spoiling, but some others may come across it too so be careful. Re:Yeah,right said ,It took me a lot of time to think a correct mathematical solution before hosting the problem. Last edit: 2012-07-15 17:21:44 |
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2013-09-04 04:43:08 devu
Solutions are rejudged,Damian Straszak and Anton Lunyov are accepted, I uploaded the previous input output file,sorry for the inconvinience caused. I hope in my next problem ,i will not make this error for sure. |