combination unranking(uint64_t num, uint16_t k, uint16_t n)
{
std::vector<uint16_t> c;
uint16_t max = n;
for (uint16_t i = k; i >= 1; i--)
{
if (num <= 0) {
c.push_back(i-1);
} else {
for (; max >= 1;)
{
uint64_t c_max_i = cnr(max, i);
if (num >= c_max_i) {
c.push_back(max);
num -= c_max_i;
max --;
break;
} else {
max --;
}
}
}
}
std::sort(c.begin(), c.end());
return c;
}
static void TopLeft(
double &top,
double &left,
const THmgphy &T,
int gW,
int gH,
double trim )
{
vector<Point> cnr( 4 );
cnr[0] = Point( trim, trim );
cnr[1] = Point( gW-1-trim, trim );
cnr[2] = Point( gW-1-trim, gH-1-trim );
cnr[3] = Point( trim, gH-1-trim );
T.Transform( cnr );
top = BIGD;
left = BIGD;
for( int k = 0; k < 4; ++k ) {
top = fmin( top, cnr[k].y );
left = fmin( left, cnr[k].x );
}
}
uint64_t ranking(const combination& c)
{
std::vector<uint16_t> v(c);
std::sort(v.begin(), v.end());
uint64_t n = 0;
// sum of C(v[k - 1], k)
for (size_t i = 1; i <= v.size(); i ++) {
n += cnr(v[i - 1], i);
}
return n;
}
void main(void)
{
int n, r;
char line[100];
printf("\nCombinatorial Coefficient by Addition");
printf("\n=====================================");
printf("\n\nN ---> ");
gets(line);
n = atoi(line);
printf( "R ---> ");
gets(line);
r = atoi(line);
printf("\nC(%d,%d) = %lu", n, r, cnr(n,r));
}
// Fill in the range of coords [x0,xL); [y0,yL) in the scape
// that the given tile will occupy. This tells the painter
// which region to fill in.
//
// We expand the tile by one pixel to be conservative, and
// transform the tile bounds to scape coords. In no case are
// the scape coords to exceed [0,ws); [0,hs).
//
static void ScanLims(
int &x0,
int &xL,
int &y0,
int &yL,
int ws,
int hs,
const TAffine &T,
int wi,
int hi )
{
double xmin, xmax, ymin, ymax;
xmin = BIGD;
xmax = -BIGD;
ymin = BIGD;
ymax = -BIGD;
vector<Point> cnr( 4 );
// generous box (outset 1 pixel) for scanning
cnr[0] = Point( -1.0, -1.0 );
cnr[1] = Point( wi, -1.0 );
cnr[2] = Point( wi, hi );
cnr[3] = Point( -1.0, hi );
T.Transform( cnr );
for( int k = 0; k < 4; ++k ) {
xmin = fmin( xmin, cnr[k].x );
xmax = fmax( xmax, cnr[k].x );
ymin = fmin( ymin, cnr[k].y );
ymax = fmax( ymax, cnr[k].y );
}
x0 = max( 0, (int)floor( xmin ) );
y0 = max( 0, (int)floor( ymin ) );
xL = min( ws, (int)ceil( xmax ) );
yL = min( hs, (int)ceil( ymax ) );
}
