SchroederPaths
A name from the enumeratio catalogue with no kernel of its own yet; this page carries its crosswalk only.
Catalogued in the enumeratio database, with crosswalk rows in oeis; not yet written up here.
SchroederPaths(...)Catalogued in the enumeratio database, with crosswalk rows in oeis; not yet written up here.Typed signatures
| Type | Package | Applies |
|---|---|---|
(integer<0..>) -> indexed_collection<schroeder_path> | combinatorics | always |
Definition
Epsil, as the implementation runs it.
count(_n)
0 if 0 > _n else _tables[2 * _n * (_n + 1) + 0 + 1]unrank(_n, _r)
Drop(Fold(Function(us if us[3] == 0 else Apply(
(uc0: integer) => Join(
[
us[1] -
0,
us[2] +
1,
us[3] -
1,
1,
],
Drop(us, 4),
[1],
) if us[1] <
uc0 else Apply(
(uc1: integer) => Join([
us[1] - uc0,
us[2] + 0,
us[3] - 2,
1,
], Drop(us, 4), [2]) if us[1] <
uc0 + uc1 else Join([us[1] -
(uc0 + uc1), us[2] - 1, us[3] - 1, 1], Drop(us, 4), [-1]),
(0 if us[2] + 0 >
_n else _tables[(us[3] - 2) *
(_n + 1) +
us[2] + 0 +
1]) if 2 <= us[3] &&
us[2] + 0 >=
0 else 0,
),
(0 if us[2] + 1 > _n else _tables[(us[3] - 1) *
(_n + 1) +
us[2] + 1 +
1]) if 1 <= us[3] &&
us[2] + 1 >=
0 else 0,
), us, ui), [_r, 0, 2 * _n, 1], Range(
1,
2 * _n,
1,
)), 4)rank(_n, _x)
Fold(Function(Apply(
(rc0: integer) => [rs[1] + 0, rs[2] + 1, rs[3] - 1, 1] if rx ==
1 else Apply(
(rc1: integer) => [
rs[1] + rc0,
rs[2] + 0,
rs[3] - 2,
1,
] if rx == 2 else [rs[1] +
rc0 + rc1, rs[2] - 1, rs[3] - 1, 1],
(0 if rs[2] + 0 >
_n else _tables[(rs[3] - 2) *
(_n + 1) +
rs[2] + 0 +
1]) if 2 <= rs[3] &&
rs[2] + 0 >=
0 else 0,
),
(0 if rs[2] + 1 > _n else _tables[(rs[3] - 1) * (_n + 1) +
rs[2] + 1 + 1]) if 1 <= rs[3] && rs[2] +
1 >= 0 else 0,
), rs, rx), [0, 0, 2 * _n, 1], _x)[1]valid(_n, _x)
Apply(
(ve: list<integer>) => ve[1] == 0 && ve[2] == 2 * _n,
Fold(
Function(vs if vs[1] < 0 else [
vs[1] + 1,
vs[2] + 1,
Max(vs[3], vs[1] + 1),
] if vx == 1 else [
vs[1] + 0,
vs[2] + 2,
Max(
vs[3],
vs[1] + 0,
),
] if vx == 2 else [
vs[1] -
1,
vs[2] +
1,
Max(vs[3], vs[1] - 1),
] if vx == -1 else [-1, 0, 0], vs, vx),
[0, 0, 0],
_x,
),
)tables(_n)
Fold(
Function(
Join(
t_t,
Fold(
Function(
ReplaceAt(
t_row,
t_c + 1,
0 if t_s < t_c else (t_t[(t_s -
1) *
(_n +
1) + t_c +
1 +
1] if t_c +
1 <=
_n else 0) +
(t_t[(t_s -
2) *
(_n +
1) + t_c +
0 +
1] if t_s >=
2 else 0) +
(t_t[(t_s -
1) *
(_n +
1) +
(t_c -
1) + 1] if t_c -
1 >=
0 else 0),
),
t_row,
t_c,
),
Map(Function(0, t_z), Range(0, _n + 1 - 1, 1)),
Range(0, _n + 1 - 1, 1),
),
),
t_t,
t_s,
),
Fold(
Function(
ReplaceAt(t_row, t_c + 1, 1 if t_c == 0 else 0),
t_row,
t_c,
),
Map(Function(0, t_z), Range(0, _n + 1 - 1, 1)),
Range(0, _n + 1 - 1, 1),
),
Range(1, 2 * _n + 1 - 1, 1),
)Enumeration
Examples
About
| Examples | 2 |
|---|---|
| Crosswalk | OEIS ×2 |