1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
// https://quuxplusone.github.io/blog/2019/03/06/pythagorean-triples/
#include <stc/algo/coroutine.h>
#include <stdio.h>
int gcd(int a, int b) {
while (b) {
int t = a % b;
a = b;
b = t;
}
return a;
}
void triples_vanilla(int n) {
for (int c = 5, i = 0; n; ++c) {
for (int a = 1; a < c; ++a) {
for (int b = a + 1; b < c; ++b) {
if ((int64_t)a*a + (int64_t)b*b == (int64_t)c*c && gcd(a, b) == 1) {
printf("%d: {%d, %d, %d}\n", ++i, a, b, c);
if (--n == 0) goto done;
}
}
}
}
done:;
}
struct triples {
int size, count;
int a, b, c;
int cco_state;
};
int triples_coro(struct triples* t) {
cco_routine(t) {
t->count = 0;
for (t->c = 5; t->size; ++t->c) {
for (t->a = 1; t->a < t->c; ++t->a) {
for (t->b = t->a + 1; t->b < t->c; ++t->b) {
if ((int64_t)t->a*t->a + (int64_t)t->b*t->b == (int64_t)t->c*t->c) {
if (t->count++ == t->size)
cco_return;
cco_yield();
}
}
}
}
cco_cleanup:
puts("done");
}
return 0;
}
int main(void)
{
puts("Vanilla triples:");
triples_vanilla(5);
puts("\nCoroutine triples:");
struct triples t = {.size=INT32_MAX};
int n = 0;
while (triples_coro(&t)) {
if (gcd(t.a, t.b) > 1)
continue;
if (t.c < 100)
printf("%d: {%d, %d, %d}\n", ++n, t.a, t.b, t.c);
else
cco_stop(&t);
}
}
|
