//naked subset column
int rule9( struct Sudoku* sud, unsigned int x, unsigned int y ) {
unsigned int i, changed, subset, ctPartners;
unsigned int partners[5];
for( subset = 5; subset >= 3; subset-- ) {
if( __popcnt64( sud->grid[y][x] ) > subset ) continue;
if( __popcnt64( sud->contains[CONTAINS_COL][y] ) < subset ) continue;
ctPartners = 0;
for( i = 0; i < sud->length; i++ ) {
if( ( i != y ) && ( sud->grid[i][x] & sud->grid[y][x] ) && ( ( sud->grid[i][x] & ( ~sud->grid[y][x] ) ) == 0 ) ) {
partners[ctPartners++] = i;
}
}
if( ctPartners != subset ) continue;
changed = 0;
for( i = 0; i < sud->length; i++ ) {
changed |= ( sud->grid[i][x] & ( ~sud->grid[y][x] ) );
sud->grid[i][x] &= ( ~sud->grid[y][x] );
}
return changed;
}
return 0;
}
//naked subset row
int rule11( struct Sudoku* sud, unsigned int x, unsigned int y ) {
struct Combinator c;
SudokuCell cellok;
SudokuCell subset;
SudokuCell changed;
unsigned int i, j, k;
unsigned int index[64] = { 0 };
unsigned int combination[5] = { 0 };
j = 0;
for( i = 0; i < sud->length; i++ ) {
if( sud->cellvalue[y][i] == 0 && i != x ) {
index[j++] = i;
}
}
if( j <= 3 ) return 0;
for( i = 2; i < 4; i++ ) {
Combinator_Initialize( &c, i, index, j );
combination[i] = x;
while( Combinator_GetNext( &c, combination ) == 0 ) {
subset = 0;
for( j = 0; j <= i; j++ ) {
subset |= sud->grid[y][combination[j]];
for( k = j + 1; k <= i; k++ ) {
if( sud->grid[y][combination[j]] & sud->grid[y][combination[k]] ) {
cellok |= ( ( 1 << j ) | ( 1 << k ) );
break;
}
}
}
if( __popcnt64( cellok ) != i + 1 ) continue;
if( __popcnt64( subset ) != i + 1 ) continue;
changed = 0;
for( j = 0; j < sud->length; j++ ) {
if( ( cellok & ( 1ll << j ) ) == 0 ) {
changed |= ( sud->grid[y][j] & subset );
sud->grid[y][j] &= ( ~subset );
}
}
return changed != 0;
}
}
return 0;
}
int strategy5( struct Sudoku* sud, unsigned int x, unsigned int y ) {
unsigned int i, j;
SudokuCell changed;
//if cell contains more than 2 its not naked pair
if( __popcnt64( sud->grid[y][x] ) != 2 ) return 0;
for( i = 0; i < sud->length; i++ ) {
if( i == y ) continue;
//find identical partner
if( sud->grid[i][x] == sud->grid[y][x] ) {
changed = 0;
for( j = 0; j < sud->length; j++ ) {
//delete candidates from all other cells in neighbourhood
if( j != i && j != y ) {
changed |= ( sud->grid[j][x] & sud->grid[y][x] );
sud->grid[j][x] &= ( ~( sud->grid[y][x] ) );
}
}
return changed != 0;
}
}
return 0;
}
int BitCount(ulong mask)
{
#if X64POPCOUNT
return (int)__popcnt64(mask);
#else
int count = 0;
while (mask != 0)
{
count++;
mask &= mask - 1;
}
return count;
#endif
}
//Hidden pairs in Reihen
int rule7( struct Sudoku* sud, unsigned int x, unsigned int y ) {
unsigned int i, j;
SudokuCell candidate, neighbourhood;
for( i = 0; i < sud->length; i++ ) {
candidate = ( sud->grid[y][x] ) & ( sud->grid[y][i] );
if( __popcnt64( candidate ) == 2ll && i != x ) {
if( ( __popcnt64( sud->grid[y][x] ) != 2ll ) || ( __popcnt64( sud->grid[y][i] ) != 2ll ) ) {
neighbourhood = 0;
for( j = 0; j < sud->length; j++ ) {
if( j != i && j != x ) neighbourhood |= sud->grid[y][j];
}
if( ( candidate & neighbourhood ) == 0 ) {
sud->grid[y][i] = candidate;
sud->grid[y][x] = candidate;
return 1;
}
}
return 0;
}
}
return 0;
}
//Naked pairs box
int rule6( struct Sudoku* sud, unsigned int x, unsigned int y ) {
unsigned int i, j;
SudokuCell changed;
if( __popcnt64( sud->grid[y][x] ) != 2 ) return 0;
for( i = 0; i < sud->length; i++ ) {
if( ( ( sud->grid[y][x] ) == ( *sud->cellbox[y][x][i] ) ) && ( &sud->grid[y][x] ) != sud->cellbox[y][x][i] ) {
changed = 0;
for( j = 0; j < sud->length; j++ ) {
if( (j != i) && (sud->cellbox[y][x][j] != &sud->grid[y][x])) {
changed |= ( ( *sud->cellbox[y][x][j] ) & sud->grid[y][x] );
*sud->cellbox[y][x][j] &= ( ~( sud->grid[y][x] ) );
}
}
return changed != 0;
}
}
return 0;
}
Size countBits(Size a) {
#ifdef __GNUC__
#ifdef __X64__
return __builtin_popcountl(a);
#else
return __builtin_popcount(a);
#endif
#elif defined(_MSC_VER)
#ifdef __X64__
return __popcnt64(a);
#else
return __popcnt(a);
#endif
#else
//Very naive implementation.
Size c = 0;
while(a) {
if(a & 1) c++;
a >>= 1;
}
return c;
#endif
}
//:/
int rule15( struct Sudoku* sud, unsigned int x, unsigned int y ) {
struct Combinator c;
SudokuCell cellok;
SudokuCell subset;
SudokuCell changed;
unsigned int i, j, k;
unsigned int index[64] = { 0 };
unsigned int combination[5] = { 0 };
unsigned int curcell = BOXINDEX( sud, x, y );
j = 0;
for( i = 0; i < sud->length; i++ ) {
if( *sud->cellboxvalue[y][x][i] == 0 && i != curcell ) {
index[j++] = i;
}
}
if( j <= 3 ) return 0;
for( i = 2; i < 4; i++ ) {
Combinator_Initialize( &c, i, index, j );
combination[i] = curcell;
while( Combinator_GetNext( &c, combination ) == 0 ) {
subset = 0ll;
for( j = 0; j <= i; j++ ) {
for( k = j + 1; k <= i; k++ ) {
if( *sud->cellbox[y][x][combination[j]] & *sud->cellbox[y][x][combination[k]] ) {
cellok |= ( ( 1 << j ) | ( 1 << k ) );
subset |= *sud->cellbox[y][x][combination[j]] & *sud->cellbox[y][x][combination[k]];
break;
}
}
}
if( __popcnt64( cellok ) != i + 1 ) continue;
for( j = 0; j < sud->length; j++ ) {
if( ( cellok & ( 1ll << j ) ) == 0 ) subset &= ( ~( *sud->cellbox[y][x][j] ) );
}
if( __popcnt64( subset ) != i + 1 ) continue;
changed = 0;
for( j = 0; j < sud->length; j++ ) {
if( ( subset & ( 1ll << j ) ) != 0 ) {
changed |= ( *sud->cellbox[y][x][j] & ( ~( subset ) ) );
*sud->cellbox[y][x][j] &= subset;
}
}
return changed != 0;
}
}
return 0;
}
static inline int
popcnt(std::uint64_t n)
{
return __popcnt64(n);
}
int strategy14( struct Sudoku* sud, unsigned int x, unsigned int y ) {
struct Combinator c;
SudokuCell cellok;
SudokuCell subset;
SudokuCell changed;
unsigned int i, j, k;
unsigned int index[64] = { 0 };
unsigned int combination[5] = { 0 };
j = 0;
//count number of empty cells in neighbourhood
for( i = 0; i < sud->length; i++ ) {
if( sud->cellvalue[x][i] == 0 && i != x ) {
index[j++] = i;
}
}
if( j <= SUDOKU_SUBSET_MIN ) return 0;
//for defined subset sizes
for( i = SUDOKU_SUBSET_MIN; i <= SUDOKU_SUBSET_MAX; i++ ) {
Combinator_Initialize( &c, i, index, j );
combination[i] = x;
//for each available combination
while( Combinator_GetNext( &c, combination ) == 0 ) {
subset = 0ll;
for( j = 0; j <= i; j++ ) {
for( k = j + 1; k <= i; k++ ) {
//combine all subsets
//create validation mask
if( sud->grid[y][combination[j]] & sud->grid[y][combination[k]] ) {
cellok |= ( ( 1 << j ) | ( 1 << k ) );
subset |= sud->grid[y][combination[j]] & sud->grid[y][combination[k]];
break;
}
}
}
//validate subset
if( __popcnt64( cellok ) != i + 1 ) continue;
for( j = 0; j < sud->length; j++ ) {
if( ( cellok & ( 1ll << j ) ) == 0 ) subset &= ( ~( sud->grid[y][j] ) );
}
if( __popcnt64( subset ) != i + 1 ) continue;
//remove other candidates from cells in subset
changed = 0;
for( j = 0; j < sud->length; j++ ) {
if( ( subset & ( 1ll << j ) ) != 0 ) {
changed |= ( sud->grid[y][j] & ( ~( subset ) ) );
sud->grid[y][j] &= subset;
}
}
return changed != 0;
}
}
return 0;
}
