OpenSoure_Repos/TheAlgorithms-C-Plus-Plus
1
0
Fork 0
mirror of https://hub.njuu.cf/TheAlgorithms/C-Plus-Plus.git synced 2023-10-11 13:05:55 +08:00
Code Issues Packages Projects Releases Wiki Activity

Merge branch 'master' into circular-linked-list

Browse Source
This commit is contained in:
David Leal 2021-10-31 17:47:38 -06:00 committed by GitHub
commit 8e11bf7efb
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 17 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
math/prime_numbers.cpp
View File

@ -9,14 +9,22 @@
/** Generate an increasingly large number of primes
* and store in a list
*/
std::vector<int> primes(int max) {
max++;
std::vector<int> primes(size_t max) {
std::vector<int> res;
std::vector<bool> numbers(max, false);
for (int i = 2; i < max; i++) {
if (!numbers[i]) {
for (int j = i; j < max; j += i) numbers[j] = true;
res.push_back(i);
std::vector<bool> is_not_prime(max + 1, false);
for (size_t i = 2; i <= max; i++) {
if (!is_not_prime[i]) {
res.emplace_back(i);
}
for (int p : res) {
size_t k = i * p;
if (k > max) {
break;
}
is_not_prime[k] = true;
if (i % p == 0) {
break;
}
}
}
return res;
@ -25,9 +33,9 @@ std::vector<int> primes(int max) {
/** main function */
int main() {
std::cout << "Calculate primes up to:\n>> ";
int n;
int n = 0;
std::cin >> n;
std::vector<int> ans = primes(n);
for (int i = 0; i < ans.size(); i++) std::cout << ans[i] << ' ';
for (int p : ans) std::cout << p << ' ';
std::cout << std::endl;
}