所以我被分配了这个怪物程序
public class AirlineRoutes
{
private int[][] routes;
/**
* Creates a table with direct flight times for a group of cities.
*/
public AirlineRoutes(int[][] routes)
{
this.routes = routes;
}
/**
* Returns the shortest flying time from start to destination
* going through at most one intermediate city.
* @precondition 1 <= start <= N (where N is size of matrix)
* @precondition 1 <= destination <= N (where N is size of matrix)
* Note that cities are labeled 1 to N , whereas the matrix
* is indexed from 0 to N-1
* @param start the city to start the flight from
* @param destination the city to end the flight at
* @return returns the least number of hours going from start
* city to destination. The flight can be direct or
* have a stop in one other city - Destination travleing
* through at most one intermediate city.
*/
public int minTime(int start, int destination)
{
}
/**
* Returns a string containing a chart showing the times
* to each city in hours.
* @return a table showing the time in hours for direct
* flights from every city.
*/
public String toString()
{
String s = "\t\t\tDestination City\n\t\t";
s += "\n\t\t\t";
for (int k = 1; k <= routes[0].length; k++)
s += "\t" + k;
s += "\n\t\t";
for (int k = 0; k <= routes[0].length; k++)
s += "----";
s += "-\n";
for (int r = 0; r < routes[0].length; r++)
{
if (r == 1)
s += "Start";
else if (r == 2)
s += "City";
else
s += "\t";
s += "\t" + (r+1) + "\t|\t";
for (int c = 0; c < routes[r].length; c++)
s += routes[r][c] + "\t";
s += "\n";
}
return s;
}
}
public class AirlineRoutesDriver
{
public static void main(String[] args)
{
int[][] routes = new int[4][4];
for (int k = 0; k < routes.length; k++)
routes[k][k] = 0;
routes[0][1] = 3;
routes[0][2] = 2;
routes[0][3] = 6;
routes[1][0] = 3;
routes[1][2] = 1;
routes[1][3] = 3;
routes[2][0] = 2;
routes[2][1] = 1;
routes[2][3] = 5;
routes[3][0] = 5;
routes[3][1] = 4;
routes[3][2] = 2;
AirlineRoutes r = new AirlineRoutes(routes);
System.out.println(r);
System.out.println("From city 4 to city 1 takes " + r.minTime(4,1) + " hours");
System.out.println("From city 1 to 3 to city " + r.minTime(1,3) + " hours");
System.out.println("From city 3 to 3 to city " + r.minTime(3,3) + " hours");
}
}
public class AirlineRoutesDriver
{
public static void main(String[] args)
{
int[][] routes = new int[4][4];
for (int k = 0; k < routes.length; k++)
routes[k][k] = 0;
routes[0][1] = 3;
routes[0][2] = 2;
routes[0][3] = 6;
routes[1][0] = 3;
routes[1][2] = 1;
routes[1][3] = 3;
routes[2][0] = 2;
routes[2][1] = 1;
routes[2][3] = 5;
routes[3][0] = 5;
routes[3][1] = 4;
routes[3][2] = 2;
AirlineRoutes r = new AirlineRoutes(routes);
System.out.println(r);
System.out.println("From city 4 to city 1 takes " + r.minTime(4,1) + " hours");
System.out.println("From city 1 to 3 to city " + r.minTime(1,3) + " hours");
System.out.println("From city 3 to 3 to city " + r.minTime(3,3) + " hours");
}
}
我不知道如何处理minTime()方法。我知道我必须找到从A点到B点的最短时间，但我不知道如何将其写入代码。
非常感谢你！
更新：我找到了算法，但我不知道如何将其翻译成java
更新2：我已经开始编写代码了，我将在下面发布。它还没有完成，我需要在if语句之后发出ctr++;语句，但我不确定要放入什么...然后我还需要返回一个int这个方法
public int minTime(int start, int destination)
{
int ctr = 1;
int ran = routes.length;
int shortest = 0; //keeps track of the shortest time
int longest = 0; //keeps track of the longest time
int[][] otherArray = new int[routes.length][routes[ran].length]; //creates a new array to store the shortest time in
for (int i = 0; i < routes.length; i++)
{
for (int j = 0; j < routes[i].length; j++)
{
otherArray[ctr] = otherArray[i][j+ctr] + otherArray[j+ctr][j];
ctr++;
}
}
//return some integer here!
}
答案 0 :(得分：0)
您必须使用动态编程。
算法： 从A开始，计算到B的所有可能路径。选择最短路径。