Examples of common PHP algorithms and data structures

 ";//---------------------------------------//Common sort algorithm//---------------------------------------//bubble sort function B    Ubblesort ($arr) {$length = count ($arr);    if ($length <=1) {return $arr;                } for ($i =0; $i < $length; $i + +) {for ($j = $length; $j > $i; $j-) {if ($arr [$j]< $arr [$j-1]) {                $tmp = $arr [$j];                $arr [$j] = $arr [$j-1];            $arr [$j-1] = $tmp; }}} return $arr;} echo ' bubble sort: '; echo implode (', Bubblesort ($arr)). "
";//fast sort function QSort ($arr) {$length = count ($arr);    if ($length <=1) {return $arr;    } $pivot = $arr [0];//pivot $left _arr = array ();    $right _arr = Array ();        for ($i =1; $i < $length; $i + +) {//note $i starting from 1 0 is the pivot if ($arr [$i]<= $pivot) {$left _arr[] = $arr [$i];        }else{$right _arr[] = $arr [$i]; }} $left _arr = QSort ($left _arr);//recursive sort left half $right _arr = QSort ($right _arr);//recursive sort right half return Array_merge ($left _arr,array ($pivot), $right _arr);//merge the left half, pivot, right half}echo "quick sort:"; Echo implode (", QSort ($arr))."
";//select sort (unstable) function Selectsort ($arr) {$length = count ($arr);    if ($length <=1) {return $arr;        } for ($i =0; $i < $length; $i + +) {$min = $i;            for ($j = $i +1; $j < $length; $j + +) {if ($arr [$j]< $arr [$min]) {$min = $j;            }} if ($i! = $min) {$tmp = $arr [$i];            $arr [$i] = $arr [$min];        $arr [$min] = $tmp; }} return $arr;} echo "Select sort:"; Echo implode (', Selectsort ($arr)). "
";//Insert Sort function Insertsort ($arr) {$length = count ($arr);    if ($length <=1) {return $arr;        } for ($i =1; $i < $length; $i + +) {$x = $arr [$i];        $j = $i-1;            while ($x < $arr [$j] && $j >=0) {$arr [$j +1] = $arr [$j];        $j--;    } $arr [$j +1] = $x; } return $arr;} echo ' Insert sort: '; echo implode (', Insertsort ($arr)). "
";//---------------------------------------//Common lookup algorithm//---------------------------------------//two points find function b        Inary_search ($arr, $low, $high, $key) {while ($low <= $high) {$mid = Intval (($low + $high)/2);        if ($key = = $arr [$mid]) {return $mid +1;        }elseif ($key < $arr [$mid]) {$high = $mid-1;        }elseif ($key > $arr [$mid]) {$low = $mid +1; }} return-1;} $key = 6;echo "binary finds the location of {$key}:" Echo Binary_search (QSort ($arr), 0,8, $key);//Order Lookup function Sqsearch ($arr, $key) {$length =    Count ($arr);        for ($i =0; $i < $length; $i + +) {if ($key = = $arr [$i]) {return $i +1; }} return-1;} $key = 8;echo "
Order General Lookup {$key} location: "; Echo Sqsearch ($arr, $key);//---------------------------------------//Common data structure//--------------    Delete of-------------------------///Linear table (array implementation) function Delete_array_element ($arr, $pos) {$length = count ($arr);    if ($pos <1 | | $pos > $length) {return "Error deleting location!";    } for ($i = $pos-1; $i < $length-1; $i + +) {$arr [$i] = $arr [$i +1];    } array_pop ($arr); return $arr;} $pos = 3;echo "
After the element in the position {$pos}: "; Echo implode (', Delete_array_element ($arr, $pos))."
";/** * Class Node * PHP analog List of basic operations */class node{public $data = '; public $next = null;} Initialize function init ($linkList) {$linkList->data = 0;//to record the length of the list $linkList->next = null;}        Head interpolation creates a list of function Createhead (& $linkList, $length) {for ($i =0; $i < $length; $i + +) {$newNode = new Node ();        $newNode->data = $i;        $newNode->next = $linkList->next;//Because the object itself in PHP is a reference so no longer available "&" $linkList->next = $newNode;    $linkList->data++;    }}//tail interpolation creates a linked list function Createtail (& $linkList, $length) {$r = $linkList;        for ($i =0; $i < $length; $i + +) {$newNode = new Node ();        $newNode->data = $i;        $newNode->next = $r->next;        $r->next = $newNode;        $r = $newNode;    $linkList->data++; }}//inserts the specified element function insert ($linkList, $pos, $elem) at the specified location {if ($pos <1 && $pos > $linkList->data+1) {Ech o "wrong insertion position!    ";    } $p = $linkList;    for ($i =1; $i < $pos; $i + +) {$p = $p->next;} $newNode = new Node ();    $newNode->data = $elem;    $newNode->next = $p->next; $p->next = $newNode;} Removes the element at the specified location, function delete ($linkList, $pos) {if ($pos <1 && $pos > $linkList->data+1) {echo "position does not exist!    ";    } $p = $linkList;    for ($i =1; $i < $pos; $i + +) {$p = $p->next;    } $q = $p->next;    $p->next = $q->next;    Unset ($q); $linkList->data--;}    Output list data function Show ($linkList) {$p = $linkList->next; while ($p!=null) {echo $p->data. "        ";    $p = $p->next; } Echo '
';} $linkList = new Node (), Init ($linkList);//Initialize Createtail ($linkList, 10);//tail interpolation create linked list show ($linkList);//Print out list insert ($ linklist,3, ' a ');//Insert Show ($linkList);d elete ($linkList, 3);//delete show ($linkList);/** * Class stack * Basic operation of the sequence stack with PHP */    Class stack{//initializes the stack directly with default values, or initializes the stack private $top =-1 using the constructor method;    Private $maxSize = 5;    Private $stack = Array (); into the stack public function push ($elem) {if ($this->top >= $this->maxsize-1) {echo "stack is full!)
";        Return        } $this->top++;    $this->stack[$this->top] = $elem; }//out-Stack public function pop () {if ($this->top = =-1) {echo "stack is empty!)            ";        return;        } $elem = $this->stack[$this->top];        unset ($this->stack[$this->top]);        $this->top--;    return $elem; }//Print stack public function show () {for ($i = $this->top; $i >=0; $i-) {echo $this->stack[$i]. "        "; } echo "
"; }} $stack = new stack (); $stack->push (3); $stack->push (5); $stack->push (8); $stack->push (7); $stack Push (9); $stack->push (2); $stack->show (); $stack->pop (); $stack->pop (); $stack->pop (); $stack Show ();

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