公交车换乘算法(转)

公交车换乘算法[共同讨论和学习

//[作者：龙龙，发表时间：2006-11-15，未经同意不得转载] //本算法实现公交线路一次换乘，多次换乘算法这里不作讨论 //数据库名bus，建立数据表bus //由于此换乘算法比较简单，只需一张表bus就可以了 //表bus结构如： /** * ********************************************************************************************** * id（自动编号 pk）     busline（公交线路 int 4）   busname（站点名称 varchar 20）   busorder（站点顺序 int 4） * 1                    1                         火车站                           1 * 2                    1                         胜利广场                         2 * 3                    1                         卖渔桥                           3 * ...                  ...                       ...                             ... * 25                   2                         胜利广场                         1 * 26                   2                         天香电器城                       2 * 27                   2                         五里墩                           3 * ...                  ...                       ...                             ... * 数据库就是这样插记录的，可以把城市的公交线路数据全部插进去 ************************************************************************************************ */ //定义一个新类 //实现公交换乘 class buss{      //定义数据库连接成员变量      var $host;      var $user;      var $passwd;      var $database;      var $conn;      //利用构造函数实现变量初始化，连接数据库      function buss(){          $this->host="localhost";          $this->user="root";          $this->passwd="";          $this->database="bus";          $this->conn=mysql_connect($this->host, $this->user,$this->passwd) or          die("Could not connect to $this->host");          mysql_select_db($this->database,$this->conn) or          die("Could not switch to database $this->database");      }           //统计数据库中所有公交站点名，存入数组      //返回站点名      function busstotal(){          $SQL = "select * from bus group by busname";          $count = 0;          $result = mysql_query($SQL);          while($row = mysql_fetch_object($result)){              $bustotal[$count]= $row->busname;              $count++;          }          return $bustotal;      }           //统计数据库中所有公交路线，存入数组      //返回公交线路      function busslinetotal(){          $SQL = "select * from bus group by busline";          $count = 0;          $result = mysql_query($SQL);          while($row = mysql_fetch_object($result)){              $buslinetotal[$count]= $row->busline;              $count++;          }          return $buslinetotal;      }           //统计数据库中每一线路经过的站点，存入数组      //需要参数line，区别每一路车      //返回站点名      function bussperline($line){          $SQL = "select * from bus where busline = '$line'";          $count = 0;          $result = mysql_query($SQL);          while($row = mysql_fetch_object($result)){              $busperline[$count]= $row->busname;              $count++;          }          return $busperline;      }           //统计经过某站点的所有公交车的组合      //需要参数station，表示经过的站点      //返回公交线路      function passline($station){          $SQL = "select * from bus where busname = '$station' group by busline";          $count = 0;          $result = mysql_query($SQL);          while($row = mysql_fetch_object($result)){              $passline[$count]= $row->busline;              $count++;          }          return $passline;      }           //实现换乘算法的函数      //需要提供参数，查询的起点和终点      function bussStationToStation($start,$end){          $flag1 = false;          $flag2 = false;          //函数回调          $busstotal = $this->busstotal();          $busslinetotal = $this->busslinetotal();          //判断数据库中是否有此站点          for($i=0;$i              if($start==$busstotal[$i]) $flag1 = true;              if($end==$busstotal[$i]) $flag2 = true;              if($flag1 and $flag2) break;          }          //有一个站点不存在          if(!($flag1 and $flag2)){              if(!$flag1) die("$start站点不存在！");              if(!$flag2) die("$end站点不存在！");          }          //两个站点都存在的情况          //首先判断有无直达车          $strTemp = "";          //遍历所有车次          for($i=0;$i              $flag3 = 0;              //函数回调              $bussperline = $this->bussperline($busslinetotal[$i]);              //遍历每一车次经过的站点              for($j=0;$j                  if($start==$bussperline[$j]) $flag3 +=1;                  if($end==$bussperline[$j]) $flag3 +=1;                  if($flag3==2) break;              }              if($flag3==2)              //保存直达车次，以||分割              $strTemp = $strTemp.$busslinetotal[$i]."||";          }          if($strTemp==""){              //没有直达车，则计算一次换乘情况              echo("".$start. " 到 "              .$end." 没有直达车!请参 照下列换乘建议. ");              //查询一级中转站              //start起点              //end终点              //函数回调，取得经过起点和终点的所有组合              $statpass = $this->passline($start);              $endpass = $this->passline($end);              //得到经过起点和终点的线路的全部组合              $resultbus = "";              for($a=0;$a                  for($b=0;$b                      //判断两条线路有没有交叉点                      $startper = $this->bussperline($statpass[$a]);                      $endper = $this->bussperline($endpass[$b]);                      for($c=0;$c                          for($d=0;$d                              if($startper[$c]==$endper[$d]){                                  //成功找到交叉点后                                  //存储交叉点处信息                                  //此只为一次换乘                                  $fistid = $statpass[$a];                                  $secondid = $endpass[$b];                                  $changestation = $startper[$c];                                  $resultbus .= $fistid.";".$secondid.";".$changestation."||";                              }                          }                      }                                       }              }              if($resultbus=="")              {              //没有找到换乘线路              echo(" 抱歉，" .$start. " 到 "              .$end. "没有直达车,换乘一次也无法到达!");              }              else{                  //找到换乘线路                  $resultbus = substr($resultbus,0,strlen($resultbus)-2);//去掉最右边的"||"                  $resultbus_ok1 = explode("||",$resultbus);//将字符串分割成数组                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  for($mm=0;$mm                      $resultbus_ok2 = explode(";",$resultbus_ok1[$mm]);                      //计算两辆车的起点和终点                      $bus1 = $this->bussperline($resultbus_ok2[0]);                      $bus2 = $this->bussperline($resultbus_ok2[1]);                      //显示                      echo ("");                      echo ("");                      echo ("");                      echo ("");                      echo ("");                      echo ("");                      echo("");                  }                  echo(" 起点 车次 中转站 车次 终点 " .$bus1[0]. " " .$resultbus_ok2[0]. " " .$resultbus_ok2[2]. " ==> " .$resultbus_ok2[1]. " " .$bus2[count($bus2)-1]. " ");              }          }          else{              //有直达车，直接显示直达车情况              echo ("");              echo ("");              echo ("");              echo ("");              echo ("");              echo ("");              echo ("");              echo ("");              echo ("");              $strTemp = substr($strTemp,0,strlen($strTemp)-2);//去掉最右边的"||"              $strTemp_ok1 = explode("||",$strTemp);//将字符串分割成数组              for($nn=0;$nn                  //计算车辆的起点和终点                  $bus = $this->bussperline($strTemp_ok1[$nn]);                  //显示                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  echo ("");                  echo("");              }              echo(" 车次 起点 经过 经过 终点 详情 " .$strTemp_ok1[$nn]. " " .$bus[0]. " " .$start. " ==> " .$end. " " .$bus[count($bus)-1]. " 详情 ");          }      } } /* 定义好抽象类后，使用就非常简单了 */ $bus = new buss; $bus->bussStationToStation("火车站","五里墩"); //一切ok，直接就可以看到结果了 ?>

转载于:https://www.cnblogs.com/silvester/archive/2008/01/01/1694764.html