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LongestPathLength ​

The edges of the longest path.

✓ checked against that system · ! checked, with disagreements (hover a chip)FindStatSt001120via LabeledGraph✓
LongestPathLength(graph)The edges of the longest path.
Typed signatures
TypePackageApplies
(labeled_graph) -> numbercombinatoricsalways

Domain: Graph statistics

Details
  • Defined over LabeledGraph as an expression in _x, evaluated by compute-engine — the definition IS the implementation.
  • Takes a LabeledGraph and nothing else — it reads values against their positions, or walks the orbits, so it needs the bijection. Applying it to a bare list is a type error, not a wrong answer.
  • FindStat's St001120. The graph with no vertices gives 0.

Definition

Epsil, as the implementation runs it.

on LabeledGraph, over _x

0 if _x[1] == 0 else Apply((n: integer) => Apply((edges: list<list<integer>>) => Apply(
                                                                                        (totals: list<integer>) => Apply(
                                                                                                                          (adjacency: list<list<integer>>) => Apply(
                                                                                                                                                                     (paths: list<integer>) => Max(Map(Function(totals[s + 1] -
                                                                                                                                                                                                                1 if Max(Sum(Map(Function(paths[(s - 1) *
                                                                                                                                                                                                                                               n +
                                                                                                                                                                                                                                               e +
                                                                                                                                                                                                                                               1], e), Range(1, n))), 0) >
                                                                                                                                                                                                                    0 else 0, s), Range(1, 2 ^ n -
                                                                                                                                                                                                                                          1))),
                                                                                                                                                                     Apply((a_init: list<integer>) => Fold((a: list<integer>, b) => Apply(
                                                                                                                                                                                                                                           (a_next: list<integer>) => a_next,
                                                                                                                                                                                                                                           Join(a, Map(Function((1 if b ==
                                                                                                                                                                                                                                                                      2 ^
                                                                                                                                                                                                                                                                      (e - 1) else Max(Sum(Map(Function((1 if (b -
                                                                                                                                                                                                                                                                                                        2 ^
                                                                                                                                                                                                                                                                                                        (e - 1)) %
                                                                                                                                                                                                                                                                                                       2 ^ w >=
                                                                                                                                                                                                                                                                                                       2 ^
                                                                                                                                                                                                                                                                                                       (w - 1) else 0) *
                                                                                                                                                                                                                                                                                                 adjacency[w][e] *
                                                                                                                                                                                                                                                                                                 a[(b -
                                                                                                                                                                                                                                                                                                    2 ^
                                                                                                                                                                                                                                                                                                    (e - 1) -
                                                                                                                                                                                                                                                                                                    1) *
                                                                                                                                                                                                                                                                                                   n +
                                                                                                                                                                                                                                                                                                   w +
                                                                                                                                                                                                                                                                                                   1], w), Range(1, n))), 0)) if b %
                                                                                                                                                                                                                                                                                                                             2 ^ e >=
                                                                                                                                                                                                                                                                                                                             2 ^
                                                                                                                                                                                                                                                                                                                             (e - 1) else 0, e), Range(1, n))),
                                                                                                                                                                                                                                         ), a_init, Range(1, 2 ^ n -
                                                                                                                                                                                                                                                            1)), [0]),
                                                                                                                                                                   ),
                                                                                                                          Map(
                                                                                                                               Function(Map(Function(Max(Sum(Map(Function((1 if e[1] == i else 0) *
                                                                                                                                                                          (1 if e[2] == j else 0) +
                                                                                                                                                                          (1 if e[1] == j else 0) *
                                                                                                                                                                          (1 if e[2] == i else 0), e), edges)), 0), j), Range(1, n)), i),
                                                                                                                               Range(1, n),
                                                                                                                             ),
                                                                                                                        ),
                                                                                        Map(
                                                                                             Function(Max(Sum(Map(Function(1 if m %
                                                                                                                                2 ^ v >=
                                                                                                                                2 ^
                                                                                                                                (v - 1) else 0, v), Range(1, n))), 0), m),
                                                                                             Range(0, 2 ^ n -
                                                                                                      1),
                                                                                           ),
                                                                                      ), _x[2]), _x[1])

Examples

Basic #

the graph on 4 vertices with the edges 12, 23, 24 and 34

live ↗
InLongestPathLength(LabeledGraph⁡((4,[[1,2],[2,3],[2,4],[3,4]])))\mathrm{LongestPathLength}(\operatorname{LabeledGraph}((4,\bigl\lbrack\bigl\lbrack1, 2\bigr\rbrack, \bigl\lbrack2, 3\bigr\rbrack, \bigl\lbrack2, 4\bigr\rbrack, \bigl\lbrack3, 4\bigr\rbrack\bigr\rbrack)))Out33
Properties #

FindStat's value for ([],1)

live ↗
InCombinatorialStat(LabeledGraph⁡((1,[])),LongestPathLength)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((1,\bigl\lbrack\bigr\rbrack)), \text{LongestPathLength})Out00

Known value · FindStat St001120

FindStat's value for ([],2)

live ↗
InCombinatorialStat(LabeledGraph⁡((2,[])),LongestPathLength)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((2,\bigl\lbrack\bigr\rbrack)), \text{LongestPathLength})Out00

Known value · FindStat St001120

FindStat's value for ([],3)

live ↗
InCombinatorialStat(LabeledGraph⁡((3,[])),LongestPathLength)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((3,\bigl\lbrack\bigr\rbrack)), \text{LongestPathLength})Out00

Known value · FindStat St001120

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Examples4
CrosswalkFindStat