qddddr

// this tail recursive implementation can't be optimized by gcc 4.8.1.

#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

const int N = 1e5;

qddddr

/*
 * Project Euler - Problem 156
 *
 * g++ -std=c++11 -O4 156.cpp; time ./a.out
 * real	0m0.040s
 * user	0m0.036s
 * sys	0m0.000s
 */

#include <iostream>

qddddr

/*
 * Project Euler - Problem 337 (test, O(N^2))
 */

#include <iostream>
#include <vector>
#include <algorithm>
#include <cinttypes>

using namespace std;

qddddr

int main(void)
{
  const int N = 10, n = 2;
  enum_coprimes_with_stern_brocot_tree(N, 0, n, n, n);
  cout << "--------------------" << endl;
  enum_coprimes_with_reverse_euclid(N, n, n);
}

qddddr

#!r6rs

(import (rnrs))

(define (print . args)
  (for-each display args)
  (newline))

(define (enum-coprimes/stern-brocot-tree N)
  (let recur ([a 0] [b 1] [x 1] [y 1])

qddddr

#include <iostream>

using namespace std;

void enum_coprimes_with_stern_brocot_tree(int N, int a, int b, int x, int y)
{
  int n = a+x, d = b+y;
  if (d <= N) {
    cout << n << ", " << d << endl;
    enum_coprimes_with_stern_brocot_tree(N, a, b, n, d);

qddddr

/*
 * Project Euler - Problem 441
 * Brute forcing and parallelized with OpenMP 3.0
 */
 
#include <iostream>
#include <algorithm>
#include <cinttypes>
#include <omp.h>
#include <boost/multiprecision/cpp_int.hpp>

qddddr

/*
 * Project Euler - Problem 441 (Brute forcing)
 */

#include <iostream>
#include <algorithm>
#include <cinttypes>
#include <omp.h>
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>

qddddr

#!r6rs

;; Project Euler - Problem 401
;; Order = O(sqrt(N))
;;
;; $ time racket 401.sps
;; *********
;;
;; real 0m43.008s
;; user 0m41.420s

qddddr

/*
 * Project Euler - Problem 432
 * A brute force approach with cache-friendly and parallelized implementation.
 *
 * $ g++ -std=c++11 -O4 -fopenmp 432.cpp; time ./a.out
 *    N:      real       user
 *  1e6:    0.015s     0.076s
 *  1e7:    0.025s     0.212s
 *  1e8:    0.138s     1.488s
 *  1e9:    1.206s    13.368s