void add_edge(word_t u, word_t v) {
assert(u < MAXNODES);
assert(v < MAXNODES);
v += MAXNODES; // distinguish partitions
if (adjlist[u] != NIL && adjlist[v] != NIL) { // possibly part of a cycle
sols[nsols][0] = nlinks/2;
assert(!visited.test(u));
cycles_with_link(1, u, v);
}
word_t ulink = nlinks++;
word_t vlink = nlinks++; // the two halfedges of an edge differ only in last bit
assert(vlink != NIL); // avoid confusing links with NIL; guaranteed if bits in word_t > EDGEBITS + 1
links[ulink].next = adjlist[u];
links[vlink].next = adjlist[v];
links[adjlist[u] = ulink].to = u;
links[adjlist[v] = vlink].to = v;
}
void cycles_with_link(u32 len, word_t u, word_t dest) {
// printf("cycles_with_link(%d, %x, %x)\n", len, u, dest);
if (visited.test(u))
return;
if (u == dest) {
print_log(" %d-cycle found\n", len);
if (len == PROOFSIZE && nsols < MAXSOLS) {
qsort(sols[nsols++], PROOFSIZE, sizeof(word_t), nonce_cmp);
memcpy(sols[nsols], sols[nsols-1], sizeof(sols[0]));
}
return;
}
if (len == PROOFSIZE)
return;
word_t au1 = adjlist[u];
if (au1 != NIL) {
visited.set(u);
for (; au1 != NIL; au1 = links[au1].next) {
sols[nsols][len] = au1/2;
cycles_with_link(len+1, links[au1 ^ 1].to, dest);
}
visited.reset(u);
}
}
