https://codefights.com/challenge/doXskkj8PMAJ27Epk/main
try to find prime numbers by using sieve of Eratosthenes.
and count luckyprimeprime.
I think this is not difficult though.
int c, t, s, i; int luckyandprimeprime(int l, int r) { int[] p = new int[100001]; s = p.length; for ( i = 2; i < s; i++, t=0) while ((t += i) < s) p[t]++; for (i = 0; i < l; i++) if (p[i] == 1) c++; for (i = l; i <= r; i++) { if (p[i] == 1) c++; if (p[c] == 1) t++; } return t; }
Recently Lucky learnt how to check if the given number is prime or not. Bunny, Lucky's friend, decided to give her a task to test her skills.
Let's call number
P Prime Prime if the number of prime numbers in the range [1, P] is prime. Bunny asked Lucky to calculate the number of Prime Prime numbers in the range [l, r]. Can you you help her?
Example
For
l = 1 and r = 10, the output should beluckyandprimeprime(l, r) = 4.
There're
4 prime numbers in the given range: 2, 3, 5 and 7. Thus, Prime Prime numbers are 3, 4, 5and 6, 4 numbers altogether.
Input/Output
- [time limit] 3000ms (java)
- [input] integer lConstraints:
1 ≤ l ≤ r. - [input] integer rConstraints:
l ≤ r ≤ 105. - [output] integerThe number of Prime Prime numbers in the range
[l, r].
Recently Lucky learnt how to check if the given number is prime or not. Bunny, Lucky's friend, decided to give her a task to test her skills.
Let's call number
P Prime Prime if the number of prime numbers in the range [1, P] is prime. Bunny asked Lucky to calculate the number of Prime Prime numbers in the range [l, r]. Can you you help her?
Example
For
l = 1 and r = 10, the output should beluckyandprimeprime(l, r) = 4.
There're
4 prime numbers in the given range: 2, 3, 5 and 7. Thus, Prime Prime numbers are 3, 4, 5and 6, 4 numbers altogether.
Input/Output
- [time limit] 3000ms (java)
- [input] integer lConstraints:
1 ≤ l ≤ r. - [input] integer rConstraints:
l ≤ r ≤ 105. - [output] integerThe number of Prime Prime numbers in the range
[l, r].
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