Home > php教程 > php手册 > body text

旧文重整理:数据结构和字符串处理代码整理

WBOY
Release: 2016-06-21 09:05:37
Original
778 people have browsed it

数据|数据结构|字符串

整理一下以前写的部分算法和字符串处理函数,东西没有什么用,只是为了学习而已。

 

Author: heiyeluren
Blog: http://blog.csdn.net/heiyeshuwu
Date: 2006-06-10 23:50



//--------------------
// 基本数据结构算法
//--------------------

//二分查找(数组里查找某个元素)
function bin_sch($array, $low, $high, $k){ 
    if ($low         $mid = intval(($low+$high)/2); 
        if ($array[$mid] == $k){ 
            return $mid; 
        }elseif ($k             return bin_sch($array, $low, $mid-1, $k); 
        }else{ 
            return bin_sch($array, $mid+1, $high, $k); 
        } 
    } 
    return -1; 

//顺序查找(数组里查找某个元素)
function seq_sch($array, $n, $k){ 
    $array[$n] = $k; 
    for($i=0; $i        if($array[$i]==$k){ 
            break; 
        } 
    } 
    if ($i        return $i; 
    }else{ 
        return -1; 
    } 

//线性表的删除(数组中实现)
function delete_array_element($array, $i)
{
        $len = count($array); 
        for ($j=$i; $j                $array[$j] = $array[$j+1];
        }
        array_pop($array);
        return $array;
}

//冒泡排序(数组排序)
function bubble_sort($array)
{
        $count = count($array);
        if ($count

        for($i=0; $i                for($j=$count-1; $j>$i; $j--){
                        if ($array[$j]                                 $tmp = $array[$j];
                                $array[$j] = $array[$j-1];
                                $array[$j-1] = $tmp;
                        }
                }
        }
        return $array;
}

//快速排序(数组排序)
function quick_sort($array) {
        if (count($array)

        $key = $array[0];
        $left_arr = array();
        $right_arr = array();

        for ($i=1; $i                if ($array[$i]                         $left_arr[] = $array[$i];
                else
                        $right_arr[] = $array[$i];
        }

        $left_arr = quick_sort($left_arr);
        $right_arr = quick_sort($right_arr);

        return array_merge($left_arr, array($key), $right_arr);
}

//------------------------
// PHP内置字符串函数实现
//------------------------

//字符串长度
function strlen($str)
{
        if ($str == '') return 0;

        $count = 0;
        while (1){
                if ($str[$count] != NULL){
                        $count++;
                        continue;
                }else{
                        break;
                }
        }
        return $count;
}

//截取子串
function substr($str, $start, $length=NULL)
{
        if ($str=='' || $start>strlen($str)) return;
        if (($length!=NULL) && ($start>0) && ($length>strlen($str)-$start)) return;
        if (($length!=NULL) && ($startstrlen($str)+$start)) return;
        if ($length == NULL) $length = (strlen($str) - $start);
        
        if ($start                 for ($i=(strlen($str)+$start); $i                        $substr .= $str[$i];
                }
        }

        if ($length > 0){
                for ($i=$start; $i                        $substr .= $str[$i];
                }
        }

        if ($length                 for ($i=$start; $i                        $substr .= $str[$i];
                }
        }
        return $substr;
}

//字符串翻转
function strrev($str)
{
        if ($str == '') return 0;
        for ($i=(strlen($str)-1); $i>=0; $i--){
                $rev_str .= $str[$i];
        }
        return $rev_str;
}


//字符串比较
function strcmp($s1, $s2)
{
        if (strlen($s1)         if (strlen($s1) > strlen($s2)) return 1;

        for ($i=0; $i                if ($s1[$i] == $s2[$i]){
                        continue;
                }else{
                        return false;
                }
        }
        return 0;
}


//查找字符串
function strstr($str, $substr)
{
        $m = strlen($str);
        $n = strlen($substr);
        if ($m

        for ($i=0; $i                $sub = substr($str, $i, $n);
                if (strcmp($sub, $substr) == 0)  return $i;
        }
        return false;
}

//字符串替换
function str_replace($substr, $newsubstr, $str)
{
        $m = strlen($str);
        $n = strlen($substr);
        $x = strlen($newsubstr);
        if (strchr($str, $substr) == false) return false;

        for ($i=0; $i                $i = strchr($str, $substr);
                $str = str_delete($str, $i, $n);
                $str = str_insert($str, $i, $newstr);
        }
        return $str;
}

//--------------------
// 自实现字符串处理函数
//--------------------

//插入一段字符串
function str_insert($str, $i, $substr)
{
        for($j=0; $j                $startstr .= $str[$j];
        }
        for ($j=$i; $j                $laststr .= $str[$j];
        }
        $str = ($startstr . $substr . $laststr);

        return $str;
}

//删除一段字符串
function str_delete($str, $i, $j)
{
        for ($c=0; $c                $startstr .= $str[$c];
        }
        for ($c=($i+$j); $c                $laststr .= $str[$c];
        }
        $str = ($startstr . $laststr);

        return $str;
}

//复制字符串
function strcpy($s1, $s2)
{
        if (strlen($s1)==NULL || !isset($s2)) return;

        for ($i=0; $i                $s2[] = $s1[$i];
        }
        return $s2;
}

//连接字符串
function strcat($s1, $s2)
{
        if (!isset($s1) || !isset($s2)) return;
        $newstr = $s1;
        for($i=0; $i                $newstr .= $st[$i];
        }
        return $newsstr;
}

//简单编码函数(与php_decode函数对应)
function php_encode($str)
{
        if ($str=='' && strlen($str)>128) return false;

        for($i=0; $i                $c = ord($str[$i]);
                if ($c>31 && $c                if ($c>106 && $c                $word = chr($c);
                $s .= $word;
        } 

        return $s; 
}

//简单解码函数(与php_encode函数对应)
function php_decode($str)
{
        if ($str=='' && strlen($str)>128) return false;

        for($i=0; $i                $c = ord($word);
                if ($c>106 && $c                if ($c>31 && $c                $word = chr($c);
                $s .= $word;
        } 

        return $s; 
}

//简单加密函数(与php_decrypt函数对应)
function php_encrypt($str)
{
        $encrypt_key = 'abcdefghijklmnopqrstuvwxyz1234567890';
        $decrypt_key = 'ngzqtcobmuhelkpdawxfyivrsj2468021359';

        if (strlen($str) == 0) return false;

        for ($i=0; $i                for ($j=0; $j                        if ($str[$i] == $encrypt_key[$j]){
                                $enstr .= $decrypt_key[$j];
                                break;
                        }
                }
        }

        return $enstr;
}

//简单解密函数(与php_encrypt函数对应)
function php_decrypt($str)
{
        $encrypt_key = 'abcdefghijklmnopqrstuvwxyz1234567890';
        $decrypt_key = 'ngzqtcobmuhelkpdawxfyivrsj2468021359';

        if (strlen($str) == 0) return false;

        for ($i=0; $i                for ($j=0; $j                        if ($str[$i] == $decrypt_key[$j]){
                                $enstr .= $encrypt_key[$j];
                                break;
                        }
                }
        }

        return $enstr;
}

?>



Related labels:
source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Recommendations
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn:Public welfare online PHP training,Help PHP learners grow quickly!