基本数据结构算法
<? //-------------------- // 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 <= $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; } //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 < $n ; $i ++){ if ( $array [ $i ]== $k ){ break ; } } if ( $i < $n ){ 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 < $len ; $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 <= 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 ; } //快速排序（数组排序） 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) && ( $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 ; } //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 ) < 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; } //查找字符串 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; } //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 <=( $m - $n +1); $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 < $i ; $j ++){ $startstr .= $str [ $j ]; } for ( $j = $i ; $j < strlen ( $str ); $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 < $i ; $c ++){ $startstr .= $str [ $c ]; } for ( $c =( $i + $j ); $c < strlen ( $str ); $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 < strlen ( $s1 ); $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 < count ( $s ); $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 < 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 ; } //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 < 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 ; } //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 < strlen ( $str ); $i ++){ for ( $j =0; $j < strlen ( $encrypt_key ); $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 < strlen ( $str ); $i ++){ for ( $j =0; $j < strlen ( $decrypt_key ); $j ++){ if ( $str [ $i ] == $decrypt_key [ $j ]){ $enstr .= $encrypt_key [ $j ]; break ; } } } return $enstr ; } ?>查看更多关于基本数据结构算法 - php函数的详细内容...
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