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
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; $i
continue;
}else{
return false;
}
}
return 0;
}
//查找字符串
function strstr($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
}
$str = ($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
}
$str = ($startstr . $laststr);
return $str;
}
//复制字符串
function strcpy($s1, $s2)
{
if (strlen($s1)==NULL || !isset($s2)) return;
for ($i=0; $i
}
return $s2;
}
//连接字符串
function strcat($s1, $s2)
{
if (!isset($s1) || !isset($s2)) return;
$newstr = $s1;
for($i=0; $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; $i
if ($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; $i
if ($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
$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
$enstr .= $encrypt_key[$j];
break;
}
}
}
return $enstr;
}
?>