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FRQPRIME - Frequent Prime Ranges |
A range [L..H] is called a K-Frequent Prime range if there are at least K primes amongst the numbers L, L+1, ... H. Given N and K, calculate how many subranges of the range [2..N] are K-Frequent Prime.
Input
The first line contains the number of test cases T. Each of the next T lines contains 2 integers N and K.
Output
Output T lines, one corresponding to each test case, containing the required answer.
Constraints
1 <= T <= 100
2 <= N <= 100000
0 <= K <= 10000
Example
Input: 4 2 1 5 2 5 1 9 3 Output: 1 4 9 8
Explanation
Note: For the first test case, the only valid subrange is [2..2], whereas for the second test case, the valid subranges are: [2..3], [2..4], [2..5], [3..5].
Added by: | Varun Jalan |
Date: | 2010-01-25 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: NODEJS OBJC PERL6 SQLITE VB.NET |
Resource: | own problem used for Technovanza |
hide comments
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2024-06-24 06:41:12
use eratosthenesSieve(100000 + 1) ! |
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2020-10-05 17:06:34
Sieve + Binary Search |
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2020-05-22 07:32:25
sieve + prefix sum + brute force |
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2019-11-12 11:54:29
is binary search "THE OMNIPOTENT"? |
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2017-04-25 11:32:39
Because I couldnt compute n(n-1)/2 directly, got 7-8 times WA. Disgusting :| Just go on adding 'n' to sum (n-1) times. |
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2017-04-25 10:52:33
@Varun. When I try to perform following action: long long num = 100000 * (100000-1); cout<<num<<endl; following is the O/P on codechef: 1409965408 But wwhen I do: long long num = 100000000000; cout<<num<<endl; it gives: 100000000000 Also, the size of long long is 8 bytes which is 1.8446744e+19 Any idea? I have got WA multiple times due to this :( Last edit: 2017-04-25 10:58:44 |
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2017-03-14 17:11:26
No Need Of Binary Search....Think Simple |
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2017-03-12 13:24:50 shahzada
use long long ...costed me 2 WA. |
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2017-02-20 14:45:01
O(pi(N)) , where pi(N) is the number of primes in [2...N] No binary search required. Last edit: 2017-02-21 03:21:24 |
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2017-01-24 07:39:48 Anand
not casting n to long while division costed me 4 WA |