84 lines
1.9 KiB
Rust
84 lines
1.9 KiB
Rust
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/*
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* Copyright (C) 2025 Nicolás Ortega Froysa <nicolas@ortegas.org>
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* Author: Nicolás Ortega Froysa <nicolas@ortegas.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @brief Work on a segment.
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*
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* @param start:usize Beginning of the segment (inclusive).
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* @param end:usize End of the segment (inclusive).
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*
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* @return List of primes found in segment.
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*/
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pub fn work_segment(start:usize, end:usize) -> Vec<u64> {
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let mut found_primes = Vec::<u64>::new();
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let mut arr = vec![false; end - start + 1];
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if start < 2 && end > 2 {
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arr[2] = true;
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}
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if start < 3 && end > 3 {
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arr[3] = true;
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}
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let sqrt_of_num = f64::sqrt(end as f64) as usize;
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for x in 1..=sqrt_of_num {
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let xx4 = 4 * x * x;
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let xx3 = 3 * x * x;
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for y in 1..=sqrt_of_num {
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let yy = y * y;
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let n1 = xx4 + yy;
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if n1 <= end && (n1 % 12 == 1 || n1 % 12 == 5) {
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arr[n1] = !arr[n1];
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}
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let n2 = xx3 + yy;
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if n2 <= end && n2 % 12 == 7 {
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arr[n2] = !arr[n2];
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}
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if x > y {
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let n3 = xx3 - yy;
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if n3 <= end && n3 % 12 == 11 {
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arr[n3] = !arr[n3];
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}
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}
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}
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}
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for i in 5..=sqrt_of_num {
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if !arr[i] {
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continue;
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}
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let mut j = i * i;
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while j <= end {
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arr[j] = false;
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j += i * i;
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}
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}
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for i in 2..=end {
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if arr[i] {
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found_primes.push(i as u64);
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}
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}
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found_primes
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}
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