Binary Tree Setup record (PHP implementation)

The previous time has been looking at the algorithm problem, now the results of the study posted.

1. Build a common binary tree

<?phpclass Node {public    $value = 0;    public $l = null;    Public $r = null;};/ /build Tree function Buildtree ($a, $low, $high) {    if ($low > $high) {        return null;    }    $m = Floor (($low + $high)/2);    $node = new node;    $node->value = $a [$m];    $l = Buildtree ($a, $low, $m-1);    $r = Buildtree ($a, $m +1, $high);    $node->l = $l;    $node->r = $r;    return $node;}

2. Establish an ordered binary tree

<?phpclass Node {public    $value = 0;    public $l = null;    Public $r = null;};/ /ordered binary tree function insertordertree ($T, $value) {    if ($T->value = = $value) {        return;    }    if ($T->value > $value) {        if ($T->l = = = null) {            $node = new node ();            $node->value = $value;            $T->l = $node;        } else {            Insertordertree ($T->l, $value),        }    } else {        if ($T->r = = null) {            $node = new node ();            $node->value = $value;            $T->r = $node;        } else {            Insertordertree ($T->r, $value);}}}    function Buildordertree ($seq) {    $R = new Node ();    $R->value = 5;    foreach ($seq as $value) {        insertordertree ($R, $value);    }    return $R;}

3. Traversal of a two-fork tree

Middle order traversal function travel ($T) {    if ($T = = null) {        return;    }    echo $T->value, "\ n";    Travel ($T->l);    Travel ($T->r);} First Order traversal function Intravel ($T) {    if ($T = = null) {        return;    }    Intravel ($T->l);    echo $T->value, "\ n";    Intravel ($T->r);} Post-Traversal function Posttravel ($T) {    if ($T = = null) {        return;    }    Posttravel ($T->l);    Posttravel ($T->r);    echo $T->value, "\ n";} Hierarchy traversal function Leveltravel ($T) {    $q = array ();    Array_push ($q, $T);    while (!empty ($q)) {        $node = Array_shift ($q);        if ($node->l) {            Array_push ($q, $node->l);        }        if ($node->r) {            Array_push ($q, $node->r);        }        echo $node->value, "\ n";    }}

　　

Binary Tree Setup record (PHP implementation)