算法练习【旅行路线】

Car的旅行路线

问题描述

　　又到暑假了，住在城市A的Car想和朋友一起去城市B旅游。她知道每个城市都有四个飞机场，分别位于一个矩形的四个顶点上，同一个城市中两个机场之间有一 条笔直的高速铁路，第I个城市中高速铁路了的单位里程价格为Ti，任意两个不同城市的机场之间均有航线，所有航线单位里程的价格均为t。

　　那么Car应如何安排到城市B的路线才能尽可能的节省花费呢?她发现这并不是一个简单的问题，于是她来向你请教。

　　找出一条从城市A到B的旅游路线，出发和到达城市中的机场可以任意选取，要求总的花费最少。

输入格式

　　的第一行有四个正整数s，t，A，B。

　　S表示城市的个数，t表示飞机单位里程的价格，A，B分别为城市A，B的序号，(1<=A，B<=S)。

　　接下来有S行，其中第I行均有7个正整数xi1，yi1，xi2，yi2，xi3，yi3，Ti，这当中的(xi1，yi1)，(xi2，yi2)，(xi3，yi3)分别是第I个城市中任意三个机场的坐标，T I为第I个城市高速铁路单位里程的价格。

输出格式

　　共有n行，每行一个数据对应测试数据，保留一位小数。

样例输入

1
1 10 1 3
1 1 1 3 3 1 30
2 5 7 4 5 2 1
8 6 8 8 11 6 3

样例输出
47.55 数据规模和约定 　　0<S<=100，

我们先看看c语言的解法吧

#include<cstdio>
#include<algorithm>
#include<queue>
#include<iostream>
#include<cstring>
#include<cmath>
#define Inf 99999999
using namespace std;
struct City
{undefined
    float x[4];
    float y[4];
    float cost;
}city[100];
void Seek(struct City c,float &x3,float &y3)
{undefined
    if((c.x[0]-c.x[1])*(c.x[2]-c.x[1])+(c.y[0]-c.y[1])*(c.y[2]-c.y[1])==0) //直角点是（x[1],y[1]）
        {swap(c.x[0],c.x[1]);swap(c.y[0],c.y[1]);}
    else if((c.x[0]-c.x[2])*(c.x[1]-c.x[2])+(c.y[0]-c.y[2])*(c.y[1]-c.y[2])==0)//直角点是（x[2],y[2]）
        {swap(c.x[0],c.x[2]);swap(c.y[0],c.y[2]);}
    x3=c.x[1]+c.x[2]-c.x[0];
    y3=c.y[1]+c.y[2]-c.y[0];
}
float dis(struct City a,int index1,struct City b,int index2)
{undefined
    return sqrt((a.x[index1]-b.x[index2])*(a.x[index1]-b.x[index2])+(a.y[index1]-b.y[index2])*(a.y[index1]-b.y[index2]));
}
int main()
{undefined
    float G[405][405];
    int s,t,a,b;
    cin>>s>>t>>a>>b;
    for(int i=0; i<s; i++)
    {undefined
       for(int u=0;u<3;u++)
       {undefined
           cin>>city[i].x[u]>>city[i].y[u];
       }
       cin>>city[i].cost;
       float x3,y3;
       Seek(city[i],x3,y3);
       city[i].x[3]=x3;
       city[i].y[3]=y3;
    }
    for(int i=0; i<4*s; i++)
        for(int j=0; j<4*s; j++)
        {undefined
            if(i==j)
                G[i][j]=0;
            else if(i/4==j/4)
                G[i][j]=dis(city[i/4],i%4,city[j/4],j%4)*city[i/4].cost;
            else
                G[i][j]=dis(city[i/4],i%4,city[j/4],j%4)*t;
        }
for(int k=0; k<4*s; k++)
    for(int i=0; i<4*s; i++)
        for(int j=0; j<4*s; j++)
            {undefined
                G[i][j]=min(G[i][j],G[i][k]+G[k][j]);
            }
    float mindis=Inf;
    for(int i=4*a-4; i<4*a; i++)
        for(int j=4*b-4; j<4*b; j++)
        {undefined
            mindis=min(mindis,G[i][j]);
        }
    printf("%.1f\n",mindis);
    return 0;
}

java如何做？

import java.util.Scanner;

public class car的旅行路线 {
  public static void main(String[] args) {
    // TODO Auto-generated method stub
    Scanner in = new Scanner(System.in);
    int cout=in.nextInt();
    for (int ss = 0; ss <cout; ss++) {
      
    
    int s = in.nextInt();
    int t = in.nextInt();
    int A = in.nextInt();
    int B = in.nextInt();
    City []cities = new City[s];
    for(int i = 0; i < s; i++){
      int x1 = in.nextInt();
      int y1 = in.nextInt();
      int x2 = in.nextInt();
      int y2 = in.nextInt();
      int x3 = in.nextInt();
      int y3 = in.nextInt();
      int price = in.nextInt();
      City city = new City(x1, y1, x2, y2, x3, y3, price);
      cities[i] = city;
    }
    
    
    double  [][]dp = new double[s*4][s*4];
    
    for(int i = 0; i < s*4; i++){
      for( int j = 0; j < s*4 ;j++){
        if(i/4==j/4){
          dp[i][j] = dist(cities[i/4].x[i%4],cities[i/4].y[i%4],cities[j/4].x[j%4],cities[j/4].y[j%4])*cities[i/4].price;
        }else{
          dp[i][j] = dist(cities[i/4].x[i%4],cities[i/4].y[i%4],cities[j/4].x[j%4],cities[j/4].y[j%4])*t;
        }
        
        //System.out.println(i+" "+j+" "+dp[i][j]);
      }
    }
    
    
    for(int i = 0; i < 4*s;i++){
      for(int j = 0; j < 4*s; j++){
        for(int k = 0; k < 4*s; k++){
          dp[j][k] = Math.min(dp[j][k], dp[j][i]+dp[i][k]);
          //System.out.println(j+" "+k+" "+dp[j][k]);
        }
      }
    }
    
    
    
    double min = dp[(A-1)*4][(B-1)*4];
    //System.out.println(min);
    for(int i = (A-1)*4; i <A*4; i++){
      for(int j = (B-1)*4; j <B*4; j++){
        if(min>dp[i][j]){
          min = dp[i][j];
          //System.out.println(i+" "+j+" "+min);
        }
      }
    }
    
    System.out.printf("%.1f", min);
  }
  }
  private static double dist(int x12, int y12, int x22, int y22) {
    // TODO Auto-generated method stub
    return Math.sqrt((x22-x12)*(x22-x12)+(y22-y12)*(y22-y12));
  }

}


class City{
  
  int []x = new int[4];
  int []y = new int[4];
  int price;
  public City(int x1, int y1, int x2, int y2, int x3, int y3,  int price) {
    super();
    x[0] = x1;
    y[0] = y1;
    x[1] = x2;
    y[1] = y2;
    x[2] = x3;
    y[2] = y3;
    
    double t12 = dist(x1,y1,x2,y2);
    double t13 = dist(x1,y1,x3,y3);
    double t23 = dist(x2,y2,x3,y3);
    
    if(Math.abs(t12*t12+t13*t13-t23*t23)<0.000001){
      x[3] = x2+x3-x1;
      y[3] = y2+y3-y1;
    }
    
    if(Math.abs(t12*t12+t23*t23-t13*t13)<0.000001){
      x[3] = x1+x3-x2;
      y[3] = y1+y3-y2;
    }
    
    if(Math.abs(t13*t13+t23*t23-t12*t12)<0.000001){
      x[3] = x1+x2-x3;
      y[3] = y1+y2-y3;
    }
    
    this.price = price;
  }
  private double dist(int x12, int y12, int x22, int y22) {
    // TODO Auto-generated method stub
    return Math.sqrt((x22-x12)*(x22-x12)+(y22-y12)*(y22-y12));
  }

}