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SNGPG - Prime Generator The Easiest Question Ever |
Prime number questions are always being favorite to everyone. This question is extension to the problem PRIME GENERATOR. The question is very very simple and easier than that you cannot imagine. You have to count total number of such primes p in the range [a ≥ 0, b > 0] so that (p2 + 1) or/and (p2 + 2) is/are prime(s).
Input
First line of input is t, (t < 100) total number of test cases. Next t lines contains two integers a and b separated by space.
a < 50001, b < 100001 and b > a.
Output
In each line print total numbers of such prime numbers.
Example
Input: 2
0 1
4 5 Output: 2
0
[Consider 0 and 1 as prime numbers for this question]
| Added by: | AvmnuSng |
| Date: | 2013-09-08 |
| Time limit: | 5s |
| Source limit: | 50000B |
| Memory limit: | 1536MB |
| Cluster: | Cube (Intel G860) |
| Languages: | All except: ASM64 |
| Resource: | Abhimanyu Singh My Problems |
hide comments
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2019-12-13 12:07:01
if p>=5 is a prime number, then p^2 +2 is a composite........that's all |
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2019-08-14 12:50:23
Easy to solve intuitively in O(1) for every test case... Or even by a pseudo naive solution using the " segmented sieve of eratosthenes" in O(sqrt(b))... HOWEVER, to really prove the O(1) solution you will need: - Modular arithmetic - Fermat's little theorem / Euler's theorem Last edit: 2019-08-14 14:34:07 |
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2019-05-19 18:32:20
try implementing functions!! easy problem..good for beginners! |
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2018-06-22 13:45:24
When all you require is pen & paper :) |
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2018-06-20 09:46:59
0.00 AC.. 2 lines of code |
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2018-01-21 20:36:25
My 50th!! |
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2016-06-27 19:48:42
Just observe and get 0.00s. :-) |
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2016-06-18 22:49:28
took less than 15 min to solve and code !! tutorials --> |
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2016-05-10 11:51:10
NotUsingPenAndPaper Solution - 0.81s UsingPenAndPaper Solution- 0.00s |
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2016-03-09 06:28:16
python 3 lines..AC in 1st attempt |
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