Data Structure and string processing code sorting

Sort out some of the previously written algorithms and string processing functions. This is just for learning.

Author: heiyeluren
Blog: http://blog.csdn.net/heiyeshuwu
Date:

<?
//--------------------
// Basic Data Structure Algorithm
//--------------------

// Binary search (find an element in the array)
Function bin_sch ($ array, $ low, $ high, $ K ){
If ($ low <= $ high ){
$ Mid = intval ($ low + $ high)/2 );
If ($ array [$ mid] === K ){
Return $ mid;
} Elseif ($ k <$ array [$ mid]) {
Return bin_sch ($ array, $ low, $ mid-1, $ K );
} Else {
Return bin_sch ($ array, $ Mid + 1, $ high, $ K );
}
}
Return-1;
}

// Sequential search (find an element in the array)
Function seq_sch ($ array, $ N, $ K ){
$ Array [$ N] = $ K;
For ($ I = 0; $ I <$ N; $ I ++ ){
If ($ array [$ I] === K ){
Break;
}
}
If ($ I <$ n ){
Return $ I;
} Else {
Return-1;
}
}

// Delete a linear table (implemented in an array)
Function delete_array_element ($ array, $ I)
{
$ Len = count ($ array );
For ($ J = $ I; $ j <$ Len; $ J ++ ){
$ Array [$ J] = $ array [$ J + 1];
}
Array_pop ($ array );
Return $ array;
}

// Bubble sort (array sorting)
Function bubble_sort ($ array)
{
$ COUNT = count ($ array );
If ($ count <= 0) return false;

For ($ I = 0; $ I <$ count; $ I ++ ){
For ($ J = $ count-1; $ j> $ I; $ j --){
If ($ array [$ J] <$ array [$ J-1]) {
$ TMP = $ array [$ J];
$ Array [$ J] = $ array [$ J-1];
$ Array [$ J-1] = $ TMP;
}
}
}
Return $ array;
}

// Fast sorting (array sorting)
Function quick_sort ($ array ){
If (count ($ array) <= 1) return $ array;

$ Key = $ array [0];
$ Left_arr = array ();
$ Right_arr = array ();

For ($ I = 1; $ I <count ($ array); $ I ++ ){
If ($ array [$ I] <= $ key)
$ 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 built-in string function implementation
//------------------------

// String Length
Function strlen ($ Str)
{
If ($ STR = '') return 0;

$ COUNT = 0;
While (1 ){
If ($ STR [$ count]! = NULL ){
$ Count ++;
Continue;
} Else {
Break;
}
}
Return $ count;
}

// Truncate the substring
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) & ($ start <0) & ($ length> strlen ($ Str) + $ start) return;
If ($ length = NULL) $ length = (strlen ($ Str)-$ start );

If ($ start <0 ){
For ($ I = (strlen ($ Str) + $ start); $ I <(strlen ($ Str) + $ start + $ length); $ I ++ ){
$ Substr. = $ STR [$ I];
}
}

If ($ length> 0 ){
For ($ I = $ start; $ I <($ start + $ length); $ I ++ ){
$ Substr. = $ STR [$ I];
}
}

If ($ length <0 ){
For ($ I = $ start; $ I <(strlen ($ Str) + $ length); $ I ++ ){
$ Substr. = $ STR [$ I];
}
}
Return $ substr;
}

// String flip
Function strrev ($ Str)
{
If ($ STR = '') return 0;
For ($ I = (strlen ($ Str)-1); $ I> = 0; $ I --){
$ Rev_str. = $ STR [$ I];
}
Return $ rev_str;
}

// String comparison
Function strcmp ($ S1, $ S2)
{
If (strlen ($ S1) <strlen ($ S2) Return-1;
If (strlen ($ S1)> strlen ($ S2) return 1;

For ($ I = 0; $ I <strlen ($ S1); $ I ++ ){
If ($ S1 [$ I] ==$ S2 [$ I]) {
Continue;
} Else {
Return false;
}
}
Return 0;
}

// Search for strings
Function strstr ($ STR, $ substr)
{
$ M = strlen ($ Str );
$ N = strlen ($ substr );
If ($ m <$ n) return false;

For ($ I = 0; $ I <= ($ M-$ n + 1); $ I ++ ){
$ Sub = substr ($ STR, $ I, $ N );
If (strcmp ($ sub, $ substr) = 0) return $ I;
}
Return false;
}

// String replacement
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 <= ($ M-$ n + 1); $ I ++ ){
$ I = strchr ($ STR, $ substr );
$ STR = str_delete ($ STR, $ I, $ N );
$ STR = str_insert ($ STR, $ I, $ newstr );
}
Return $ STR;
}

//--------------------
// Self-implemented string processing functions
//--------------------

// Insert a string
Function str_insert ($ STR, $ I, $ substr)
{
For ($ J = 0; $ j <$ I; $ J ++ ){
$ Startstr. = $ STR [$ J];
}
For ($ J = $ I; $ j <strlen ($ Str); $ J ++ ){
$ Laststr. = $ STR [$ J];
}
$ STR = ($ startstr. $ substr. $ laststr );

Return $ STR;
}

// Delete a string
Function str_delete ($ STR, $ I, $ J)
{
For ($ C = 0; $ C <$ I; $ C ++ ){
$ Startstr. = $ STR [$ C];
}
For ($ c = ($ I + $ J); $ C <strlen ($ Str); $ C ++ ){
$ Laststr. = $ STR [$ C];
}
$ STR = ($ startstr. $ laststr );

Return $ STR;
}

// Copy the string
Function strcpy ($ S1, $ S2)
{
If (strlen ($ S1) = NULL |! Isset ($ S2) return;

For ($ I = 0; $ I <strlen ($ S1); $ I ++ ){
$ S2 [] = $ S1 [$ I];
}
Return $ S2;
}

// Connection string
Function strcat ($ S1, $ S2)
{
If (! Isset ($ S1) |! Isset ($ S2) return;
$ Newstr = $ S1;
For ($ I = 0; $ I <count ($ S); $ I ++ ){
$ Newstr. = $ st [$ I];
}
Return $ newsstr;
}

// Simple encoding function (corresponding to php_decode function)
Function php_encode ($ Str)
{
If ($ STR = ''& strlen ($ Str)> 128) return false;

For ($ I = 0; $ I <strlen ($ Str); $ I ++ ){
$ C = ord ($ STR [$ I]);
If ($ C> 31 & $ C <107) $ C + = 20;
If ($ C> 106 & $ C <127) $ C-= 75;
$ Word = CHR ($ C );
$ S. = $ word;
}

Return $ S;
}

// Simple decoding function (corresponding to the php_encode function)
Function php_decode ($ Str)
{
If ($ STR = ''& strlen ($ Str)> 128) return false;

For ($ I = 0; $ I <strlen ($ Str); $ I ++ ){
$ C = ord ($ word );
If ($ C> 106 & $ C <127) $ c = $ c-20;
If ($ C> 31 & $ C <107) $ c = $ C + 75;
$ Word = CHR ($ C );
$ S. = $ word;
}

Return $ S;
}

// Simple encryption function (corresponding to the php_decrypt function)
Function php_encrypt ($ Str)
{
$ Encrypt_key = 'abcdefghijklmnopqrstuvwxyz1234567890 ';
$ Decrypt_key = 'ngzqtcobmuhelkpdawxfyivrsj2468038559 ';

If (strlen ($ Str) = 0) return false;

For ($ I = 0; $ I <strlen ($ Str); $ I ++ ){
For ($ J = 0; $ j <strlen ($ encrypt_key); $ J ++ ){
If ($ STR [$ I] ==$ encrypt_key [$ J]) {
$ Enstr. = $ decrypt_key [$ J];
Break;
}
}
}

Return $ enstr;
}

// Simple decryption function (corresponding to the php_encrypt function)
Function php_decrypt ($ Str)
{
$ Encrypt_key = 'abcdefghijklmnopqrstuvwxyz1234567890 ';
$ Decrypt_key = 'ngzqtcobmuhelkpdawxfyivrsj2468038559 ';

If (strlen ($ Str) = 0) return false;

For ($ I = 0; $ I <strlen ($ Str); $ I ++ ){
For ($ J = 0; $ j <strlen ($ decrypt_key); $ J ++ ){
If ($ STR [$ I] ==$ decrypt_key [$ J]) {
$ Enstr. = $ encrypt_key [$ J];
Break;
}
}
}

Return $ enstr;
}

?>