INVPHI - Smallest Inverse Euler Totient Function
This task is the inverse of ETF problem, given an integer n find smallest integer i such that φ(i)=n, where φ denotes Euler's totient function.
Input
The first line is an integer T (1 ≤ T ≤ 100,000), denoting the number of test cases. Then, T test cases follow.
For each test case, there is an integer n (1 ≤ n ≤ 100,000,000) written in one line. (one integer per line)
Output
For each test case, output Smallest Inverse Euler's Totient Function of n. if n doesn't have inverse, output -1.
Example
Input: 5 10 20 30 40 50 Output: 11 25 31 41 -1
Time Limit ≈ 3*(My Program Top Speed)
hide comments
anurag garg:
2013-12-29 04:28:12
@(Tjandra Satria Gunawan)(曾毅昆)
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Sandeep Pathry:
2013-07-12 16:23:38
Finally!!! AC...
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Ritam Shukla:
2013-01-19 10:30:39
Though i have a doubt. Why is it that even if i try to run my accepted solution on ideone, it gives a runtime error SIGKILL? Is it that memory limit there is very tight? And is there any special option available there that enables us to use the Cube?
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Ritam Shukla:
2013-01-18 21:22:57
One of the finest tasks I've ever done! Great job, Tjandra. Keep it up. :)
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Ritam Shukla:
2013-01-12 20:16:19
No, not a super computer. Just a Hyperthreaded Intel Core i7-3770 4 cores 8 threads with turbo boost 3.9GHz. (I'm using without turbo currently, so I get about 3.5GHz) I think ONE MUST NOT COMPARE IDEONE WITH THE CUBE. What I believe is that ideone is equivalent to the Pyramid cluster of SPOJ, so it is bound to take >15 sec and we know that it cannot be used to time a code which takes more than 15s on Pyramid(correct me if i'm wrong). Though I just checked it out there.
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Ritam Shukla:
2013-01-12 10:05:34
@Tjandra, if you see my code, you'll realize that I precompute just once for an input file of any size, and the subsequent processing of the individual test cases (whatever their number may be) won't take more than 1-2 seconds. Moreover, the initial precomputation takes ~12-13 seconds on my PC. Even if there is some error in the logic, with so many people telling that the Cube is so fast, I expected a WA.
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Ritam Shukla:
2013-01-12 07:32:15
My brute force approach works on my system in <15 seconds but gives Time Limit Exceeded here on Cube cluster. :(
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Snehasish Roy ;):
2012-12-26 17:40:03
@Tjandra: Kindly tell whats the required complexity for the solution to be AC ?
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Ashish Lavania:
2012-12-19 08:36:22
which compilers do you guys use?
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Ashish Lavania:
2012-12-14 16:00:35
Where am I getting WA??
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Added by: | Tjandra Satria Gunawan |
Date: | 2012-09-28 |
Time limit: | 20s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | Own Problem |