// assigns to "result" size-32 vectors representing
// all elements in episode, in order, that occur at least twice
// runtime: O(N log N) where N = distance(first, last)
static void makeNoislessInputs(Episode::const_iterator first, Episode::const_iterator last, LSTMInput& result)
{
std::set<enc_t> singles(first, last);
std::set<enc_t> noise(singles);
for (Episode::const_iterator it = first; it != last; ++it) {
std::set<enc_t>::iterator sit = singles.find(*it);
if (sit != singles.end()) {
singles.erase(sit); // first occurrence
} else {
noise.erase(*it); // second occurrence means not noise
}
}
result.assign(std::distance(first, last) - noise.size(), LSTMState(32));
uint64_t i = 0;
for (Episode::const_iterator it = first; it != last; ++it) {
enc_t code = *it;
if (noise.find(code) == noise.end()) {
for (uint64_t j = 0, b = 1 << 31; j < 32; ++j, b >>= 1) {
result[i][j] = code & b ? 1 : 0;
}
++i;
}
}
}
/* Given the board state, find all possible 'moves' (i.e. squares with just
* a single digit).
*
* Returns the number of (deterministic) moves (and fills the moves array),
* or 0 if no moves are possible. This function does not mutate the board
* state, and hence, can return the same move multiple times (with
* different hints).
*/
static
int
findmoves( void )
{
int i;
rb->yield();
idx_possible = 0;
for( i = 0 ; i < 9 ; ++i )
{
singles( i, idx_row, HINT_ROW );
singles( i, idx_column, HINT_COLUMN );
singles( i, idx_block, HINT_BLOCK );
}
return idx_possible;
}
