php常用算法和数据结构

it2022-05-08  8

</pre><pre name="code" class="php"><?php      /**      * Created by PhpStorm.      * User: qishou      * Date: 15-8-2      * Time: 上午9:12      */      header("content-type:text/html;charset=utf-8");      $arr = array(3,5,8,4,9,6,1,7,2);      echo implode(" ",$arr)."<br/>";      //---------------------------------------      //              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))."<br/>";            //快速排序      function QSort($arr){          $length = count($arr);          if($length <=1){              return $arr;          }          $pivot = $arr[0];//枢轴          $left_arr = array();          $right_arr = array();          for($i=1;$i<$length;$i++){//注意$i从1开始0是枢轴              if($arr[$i]<=$pivot){                  $left_arr[] = $arr[$i];              }else{                  $right_arr[] = $arr[$i];              }          }          $left_arr = QSort($left_arr);//递归排序左半部分          $right_arr = QSort($right_arr);//递归排序右半部份          return array_merge($left_arr,array($pivot),$right_arr);//合并左半部分、枢轴、右半部分      }      echo "快速排序:";      echo implode(' ',QSort($arr))."<br/>";            //选择排序(不稳定)      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 $arr;      }      echo "选择排序:";      echo implode(' ',SelectSort($arr))."<br/>";            //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))."<br/>";      //---------------------------------------      //              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);            //顺序查找      function SqSearch($arr,$key){          $length = count($arr);          for($i=0;$i<$length;$i++){              if($key == $arr[$i]){                  return $i+1;              }          }          return -1;      }      $key = 8;      echo "<br/>顺序常规查找{$key}的位置:";      echo SqSearch($arr,$key);      //---------------------------------------      //              常用数据结构      //---------------------------------------      //线性表的删除(数组实现)      function delete_array_element($arr,$pos){          $length = count($arr);          if($pos<1 || $pos>$length){              return "删除位置出错!";          }          for($i=$pos-1;$i<$length-1;$i++){              $arr[$i] = $arr[$i+1];          }          array_pop($arr);          return $arr;      }      $pos = 3;      echo "<br/>除第{$pos}位置上的元素后:";      echo implode(' ',delete_array_element($arr,$pos))."<br/>";            /**      * Class Node      * PHP模拟链表的基本操作      */      class Node{          public $data = '';          public  $next = null;      }      //初始化      function init($linkList){          $linkList->data = 0; //用来记录链表长度          $linkList->next = null;      }      //头插法创建链表      function createHead(&$linkList,$length){          for($i=0;$i<$length;$i++){              $newNode = new Node();              $newNode->data = $i;              $newNode->next = $linkList->next;//因为PHP中对象本身就是引用所以不用再可用“&”              $linkList->next = $newNode;              $linkList->data++;          }      }      //尾插法创建链表      function createTail(&$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 "插入位置错误!";          }          $p = $linkList;          for($i=1;$i<$pos;$i++){              $p = $p->next;          }          $newNode = new Node();          $newNode->data = $elem;          $newNode->next = $p->next;          $p->next = $newNode;      }      //删除指定位置的元素      function delete($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);          $linkList->data--;      }      //输出链表数据      function show($linkList){          $p = $linkList->next;          while($p!=null){              echo $p->data." ";              $p = $p->next;          }          echo '<br/>';      }            $linkList = new Node();      init($linkList);//初始化      createTail($linkList,10);//尾插法创建链表      show($linkList);//打印出链表      insert($linkList,3,'a');//插入      show($linkList);      delete($linkList,3);//删除      show($linkList);            /**      * Class Stack      * 用PHP模拟顺序栈的基本操作      */      class Stack{          //用默认值直接初始化栈了,也可用构造方法初始化栈          private $top = -1;          private $maxSize = 5;          private $stack = array();                //入栈          public function push($elem){              if($this->top >= $this->maxSize-1){                  echo "栈已满!<br/>";                  return;              }              $this->top++;              $this->stack[$this->top] = $elem;          }          //出栈          public function pop(){              if($this->top == -1){                  echo "栈是空的!";                  return ;              }              $elem = $this->stack[$this->top];              unset($this->stack[$this->top]);              $this->top--;              return $elem;          }          //打印栈          public function show(){              for($i=$this->top;$i>=0;$i--){                  echo $this->stack[$i]." ";              }              echo "<br/>";          }      }            $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实现双向队列      */      class Deque{          private $queue = array();          public function addFirst($item){//头入队              array_unshift($this->queue,$item);          }          public function addLast($item){//尾入队              array_push($this->queue,$item);          }          public function removeFirst(){//头出队              array_shift($this->queue);          }          public function removeLast(){//尾出队              array_pop($this->queue);          }          public  function show(){//打印              foreach($this->queue as $item){                  echo $item." ";              }              echo "<br/>";          }      }      $deque = new Deque();      $deque->addFirst(2);      $deque->addLast(3);      $deque->addLast(4);      $deque->addFirst(5);      $deque->show();            //PHP解决约瑟夫环问题      //方法一      function joseph_ring($n,$m){          $arr = range(1,$n);          $i = 0;          while(count($arr)>1){              $i=$i+1;              $head = array_shift($arr);              if($i%$m != 0){ //如果不是则重新压入数组                  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 "<br/>".joseph_ring(60,5)."<br/>";      echo "<br/>".joseph_ring2(60,5)."<br/>";

转载于:https://www.cnblogs.com/keta/p/7595830.html

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