computeFrontRightToBottomRight method
int
computeFrontRightToBottomRight(
)
Implementation
int computeFrontRightToBottomRight() {
final edge = List.filled(4, Edge.upRight);
var a = 0, x = 0, b = 0;
// compute the index a < (12 choose 4) and the permutation array.
for (var j = Edge.bottomRight.index; j >= Edge.upRight.index; j--) {
if (Edge.frontRight.index <= _ep[j].index && _ep[j].index <= Edge.bottomRight.index) {
a += _cnk(11 - j, x + 1);
edge[3 - x++] = _ep[j];
}
}
// compute the index b < 4! for the permutation.
for (var j = 3; j > 0; j--) {
var k = 0;
while (edge[j].index != j + 8) {
_rotateLeft(edge, 0, j);
k++;
}
b = (j + 1) * b + k;
}
return 24 * a + b;
}