摘要：常用排序算法冒泡排序冒泡排序快速排序樞軸注意從開(kāi)始是樞軸遞歸排序左半

";  

//---------------------------------------  
//              常用排序算法  
//---------------------------------------  
//冒泡排序  
function BubbleSort($arr){  
    $length = count($arr);  
    if($length<=1){  
        return $arr;  
    }  
    for($i=0;$i<$length;$i++){  
        for($j=$length-1;$j>$i;$j--){  
            if($arr[$j]<$arr[$j-1]){  
                $tmp = $arr[$j];  
                $arr[$j] = $arr[$j-1];  
                $arr[$j-1] = $tmp;  
            }  
        }  
    }  
    return $arr;  
}  
echo "冒泡排序：";  
echo implode(" ",BubbleSort($arr))."
";  

//快速排序  
function QSort($arr){  
    $length = count($arr);  
    if($length <=1){  
        return $arr;  
    }  
    $pivot = $arr[0];//樞軸  
    $left_arr = array();  
    $right_arr = array();  
    for($i=1;$i<$length;$i++){//注意$i從1開(kāi)始0是樞軸  
        if($arr[$i]<=$pivot){  
            $left_arr[] = $arr[$i];  
        }else{  
            $right_arr[] = $arr[$i];  
        }  
    }  
    $left_arr = QSort($left_arr);//遞歸排序左半部分  
    $right_arr = QSort($right_arr);//遞歸排序右半部份  
    return array_merge($left_arr,array($pivot),$right_arr);//合并左半部分、樞軸、右半部分  
}  
echo "快速排序：";  
echo implode(" ",QSort($arr))."
";  

//選擇排序(不穩(wěn)定)  
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 $arr;  
}  
echo "選擇排序：";  
echo implode(" ",SelectSort($arr))."
";  

//插入排序  
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 $arr;  
}  
echo "插入排序：";  
echo implode(" ",InsertSort($arr))."
";  

//---------------------------------------  
//              常用查找算法  
//---------------------------------------  
//二分查找  
function binary_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;  
}  
$key = 6;  
echo "二分查找{$key}的位置：";  
echo binary_search(QSort($arr),0,8,$key);  

//順序查找  
function SqSearch($arr,$key){  
    $length = count($arr);  
    for($i=0;$i<$length;$i++){  
        if($key == $arr[$i]){  
                return $i+1;  
            }  
        }  
        return -1;  
    }  
    $key = 8;  
echo "
順序常規(guī)查找{$key}的位置：";  
echo SqSearch($arr,$key);  

//---------------------------------------  
//              常用數(shù)據(jù)結(jié)構(gòu)  
//---------------------------------------  
//線性表的刪除(數(shù)組實(shí)現(xiàn))  
function delete_array_element($arr,$pos){  
    $length = count($arr);  
    if($pos<1 || $pos>$length){  
        return "刪除位置出錯(cuò)!";  
    }  
    for($i=$pos-1;$i<$length-1;$i++){  
        $arr[$i] = $arr[$i+1];  
    }  
    array_pop($arr);  
    return $arr;  
}  
$pos = 3;  
echo "
除第{$pos}位置上的元素后：";  
echo implode(" ",delete_array_element($arr,$pos))."
";  
/** 
 * Class Node 
 * PHP模擬鏈表的基本操作 
 */  
class Node{  
    public $data = "";  
    public  $next = null;  
}  
//初始化  
function init($linkList){  
    $linkList->data = 0; //用來(lái)記錄鏈表長(zhǎng)度  
    $linkList->next = null;  
}  
//頭插法創(chuàng)建鏈表  
function createHead(&$linkList,$length){  
    for($i=0;$i<$length;$i++){  
        $newNode = new Node();  
        $newNode->data = $i;  
        $newNode->next = $linkList->next;//因?yàn)镻HP中對(duì)象本身就是引用所以不用再可用“&”  
        $linkList->next = $newNode;  
        $linkList->data++;  
    }  
}  
//尾插法創(chuàng)建鏈表  
function createTail(&$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;  
        $linkList->data++;  
    }  
}  
//在指定位置插入指定元素  
function insert($linkList,$pos,$elem){  
    if($pos<1 && $pos>$linkList->data+1){  
        echo "插入位置錯(cuò)誤！";  
    }  
    $p = $linkList;  
    for($i=1;$i<$pos;$i++){  
        $p = $p->next;  
    }  
    $newNode = new Node();  
    $newNode->data = $elem;  
    $newNode->next = $p->next;  
    $p->next = $newNode;  
}  
//刪除指定位置的元素  
function delete($linkList,$pos){  
    if($pos<1 && $pos>$linkList->data+1){  
            echo "位置不存在！";  
    }  
    $p = $linkList;  
    for($i=1;$i<$pos;$i++){  
        $p = $p->next;  
    }  
    $q = $p->next;  
    $p->next = $q->next;  
    unset($q);  
    $linkList->data--;  
}  
//輸出鏈表數(shù)據(jù)  
function show($linkList){  
    $p = $linkList->next;  
    while($p!=null){  
        echo $p->data." ";  
        $p = $p->next;  
    }  
    echo "
";  
}  
$linkList = new Node();  
init($linkList);//初始化  
createTail($linkList,10);//尾插法創(chuàng)建鏈表  
show($linkList);//打印出鏈表  
insert($linkList,3,"a");//插入  
show($linkList);  
delete($linkList,3);//刪除  
show($linkList);  
/** 
 * Class Stack 
 * 用PHP模擬順序棧的基本操作 
 */  
class Stack{  
    //用默認(rèn)值直接初始化棧了，也可用構(gòu)造方法初始化棧  
    private $top = -1;  
        private $maxSize = 5;  
    private $stack = array();  
    //入棧  
    public function push($elem){  
            if($this->top >= $this->maxSize-1){  
                echo "棧已滿！
";  
                return;  
            }  
            $this->top++;  
            $this->stack[$this->top] = $elem;  
    }  
    //出棧  
    public function pop(){  
        if($this->top == -1){  
            echo "棧是空的！";  
            return ;  
        }  
        $elem = $this->stack[$this->top];  
        unset($this->stack[$this->top]);  
        $this->top--;  
        return $elem;  
    }  
    //打印棧  
    public function show(){  
        for($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();  
/** 
 * Class Deque 
 * 使用PHP實(shí)現(xiàn)雙向隊(duì)列 
 */  
class Deque{  
    private $queue = array();  
        public function addFirst($item){//頭入隊(duì)  
        array_unshift($this->queue,$item);  
    }  
    public function addLast($item){//尾入隊(duì)  
            array_push($this->queue,$item);  
    }  
    public function removeFirst(){//頭出隊(duì)  
        array_shift($this->queue);  
    }  
    public function removeLast(){//尾出隊(duì)  
        array_pop($this->queue);  
    }  
    public  function show(){//打印  
        foreach($this->queue as $item){  
            echo $item." ";  
        }  
        echo "
";  
    }  
}  
$deque = new Deque();  
$deque->addFirst(2);  
$deque->addLast(3);  
$deque->addLast(4);  
$deque->addFirst(5);  
$deque->show();  

//PHP解決約瑟夫環(huán)問(wèn)題  
//方法一  
function joseph_ring($n,$m){  
    $arr = range(1,$n);  
    $i = 0;  
        while(count($arr)>1){  
        $i=$i+1;  
        $head = array_shift($arr);  
        if($i%$m != 0){ //如果不是則重新壓入數(shù)組  
            array_push($arr,$head);  
        }  
    }  
    return $arr[0];  
}  
    //方法二  
function joseph_ring2($n,$m){  
    $r = 0;  
    for($i=2;$i<=$n;$i++){  
        $r = ($r+$m)%$i;  
    }  
    return $r + 1;  
}  
echo "
".joseph_ring(60,5)."
";  
echo "
".joseph_ring2(60,5)."
";