C ++程序实现分段筛以生成给定范围之间的质数
这是C++程序，用于实现分段筛分以在给定范围之间生成素数。分段筛首先使用简单筛来查找小于或等于√(n)的素数。该算法的思想是将范围[0...n-1]划分为不同的段，并一一计算所有段中的素数。
算法
Begin Create function to find all primes smaller than limit using simple sieve of eratosthenes. Finds all prime numbers in given range using segmented sieve A) Compute all primes smaller or equal to square root of high using simple sieve B) Count of elements in given range C) Declaring boolean only for [low, high] D) Find the minimum number in [low ... high] that is a multiple of prime[i] (divisible by prime[i]) E) Mark multiples of prime[i] in [low … high] F) Numbers which are not marked in range, are prime End
范例程式码
#include <bits/stdc++.h>
using namespace std;
void simpleSieve(int lmt, vector<int>& prime) {
bool mark[lmt + 1];
memset(mark, false, sizeof(mark));
for (int i = 2; i <= lmt; ++i) {
if (mark[i] == false) {
prime.push_back(i);
for (int j = i; j <= lmt; j += i)
mark[j] = true;
}
}
}
void PrimeInRange(int low, int high) {
int lmt = floor(sqrt(high)) + 1;
vector<int> prime;
simpleSieve(lmt, prime);
int n = high - low + 1;
bool mark[n + 1];
memset(mark, false, sizeof(mark));
for (int i = 0; i < prime.size(); i++) {
int lowLim = floor(low / prime[i]) * prime[i];
if (lowLim < low)
lowLim += prime[i];
for (int j = lowLim; j <= high; j += prime[i])
mark[j - low] = true;
}
for (int i = low; i <= high; i++)
if (!mark[i - low])
cout << i << " ";
}
int main() {
int low = 10, high = 50;
PrimeInRange(low, high);
return 0;
}输出结果
11 13 17 19 23 29 31 37 41 43 47
热门推荐
10 香港老妈结婚祝福语简短
11 毕业立体贺卡祝福语简短
12 简短新年年会祝福语
13 评论小品祝福语大全简短
14 恭喜师兄结婚祝福语简短
15 员工集体辞职祝福语简短
16 高中新生祝福语 简短
17 装修祝福语男生搞笑简短
18 生日开业蛋糕祝福语简短