Get shortest path through nodes - php

Question

I have this array:
Array
(
[V] => Array
(
[0] => S
)
[L] => Array
(
[0] => M
[1] => Z
[2] => G
)
[S] => Array
(
[0] => T
[1] => X
[2] => K
)
[T] => Array
(
[0] => D
)
[B] => Array
(
[0] => E
[1] => N
[2] => Y
)
[W] => Array
(
[0] => J
[1] => Y
)
[G] => Array
(
[0] => A
[1] => K
)
[J] => Array
(
[0] => T
)
[X] => Array
(
[0] => H
)
[E] => Array
(
[0] => Z
)
[N] => Array
(
[0] => B
)
[Z] => Array
(
[0] => A
[1] => M
)
[U] => Array
(
[0] => R
)
[F] => Array
(
[0] => C
[1] => V
)
[I] => Array
(
[0] => F
)
[C] => Array
(
[0] => O
[1] => P
[2] => T
)
[Q] => Array
(
[0] => L
[1] => V
)
[Y] => Array
(
[0] => C
)
[K] => Array
(
[0] => T
[1] => P
[2] => A
)
[A] => Array
(
[0] => J
)
[M] => Array
(
[0] => W
)
[R] => Array
(
[0] => I
)
[P] => Array
(
[0] => K
[1] => N
)
[O] => Array
(
[0] => G
)
[H] => Array
(
[0] => Q
)
[D] => Array
(
[0] => U
)
)
Serialized:
a:26:{s:1:"V";a:1:{i:0;s:1:"S";}s:1:"L";a:3:{i:0;s:1:"M";i:1;s:1:"Z";i:2;s:1:"G";}s:1:"S";a:3:{i:0;s:1:"T";i:1;s:1:"X";i:2;s:1:"K";}s:1:"T";a:1:{i:0;s:1:"D";}s:1:"B";a:3:{i:0;s:1:"E";i:1;s:1:"N";i:2;s:1:"Y";}s:1:"W";a:2:{i:0;s:1:"J";i:1;s:1:"Y";}s:1:"G";a:2:{i:0;s:1:"A";i:1;s:1:"K";}s:1:"J";a:1:{i:0;s:1:"T";}s:1:"X";a:1:{i:0;s:1:"H";}s:1:"E";a:1:{i:0;s:1:"Z";}s:1:"N";a:1:{i:0;s:1:"B";}s:1:"Z";a:2:{i:0;s:1:"A";i:1;s:1:"M";}s:1:"U";a:1:{i:0;s:1:"R";}s:1:"F";a:2:{i:0;s:1:"C";i:1;s:1:"V";}s:1:"I";a:1:{i:0;s:1:"F";}s:1:"C";a:3:{i:0;s:1:"O";i:1;s:1:"P";i:2;s:1:"T";}s:1:"Q";a:2:{i:0;s:1:"L";i:1;s:1:"V";}s:1:"Y";a:1:{i:0;s:1:"C";}s:1:"K";a:3:{i:0;s:1:"T";i:1;s:1:"P";i:2;s:1:"A";}s:1:"A";a:1:{i:0;s:1:"J";}s:1:"M";a:1:{i:0;s:1:"W";}s:1:"R";a:1:{i:0;s:1:"I";}s:1:"P";a:2:{i:0;s:1:"K";i:1;s:1:"N";}s:1:"O";a:1:{i:0;s:1:"G";}s:1:"H";a:1:{i:0;s:1:"Q";}s:1:"D";a:1:{i:0;s:1:"U";}}
This means...
V can go to S
L can go to M, Z and G
S can go to T, X and K
...
I need an algorithm to find the shortest way from A to Z. This way should be saved as a list of the nodes, something like AJTDURIFCPNBEZ.
I just tried it with this recursion:
function getWays($key = "A") {
global $roads;
echo $key;
if($key == "Z"){
echo "<br />";
return;
}
foreach($roads[$key] as $next)
if($next != "A")
getWays($next);
}
This do not work, it is much more complicate. You have to prevent loops and increase performance (ignore long pathes early, if you already found shorter one).
Can anybody provide help?