/*
 * fw.java
 * 
 * starter file for the Floyd-Warshall problem, hw11pr2
 * 
 * Name:
 * Date:
 */

import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Arrays;

class fw
{
  
  /*
   * methods for printing objects
   */
  public static void pl(Object o) {System.out.println(o);}
  public static void p(Object o) {System.out.print(o);}
  
  /*
   * method for converting a 2d array to a string (for easy printing)
   */
  public static String toStr( int[][] A )  // 2d array
  {
     String s = "";
     int height = A.length;
     for (int row=0 ; row<height ; ++row) {
       s += Arrays.toString(A[row]) + "\n";
     }
     return s;
  }

  /*
   * ditto for 3d arrays
   */
  public static String toStr( int[][][] A )  // 3d array
  {
     String s = "";
     int depth = A.length;
     for (int slice=0 ; slice<depth ; ++slice) {
       s += "Slice " + slice + ":\n" + toStr( A[slice] ) + "\n";
     }
     return s;
  }
  
  /*
   * the main method
   */  
  public static void main( String[] args )
  { 
    Scanner kbd = new Scanner(System.in);
    System.out.print( "Enter a map filename: " );
    String filename = kbd.nextLine();
    filename = filename.trim();
    System.out.println("\nNow trying to open " + filename);
    
    Scanner file = null;
    try { // in case the file's not there
      file = new Scanner(new File(filename));
    } catch (FileNotFoundException e) {
      System.out.println("File " + filename + " not found.");
      System.out.println( e );
    }
    
    // get integer at the start of the file:
    int numcities = file.nextInt();
    System.out.println("Number of cities: " + numcities);
    
    // example of creating a 3d array
    int[][][] table = new int[4][2][3]; // 4 "slices" of 2 rows x 3 cols each
    pl( "\nThe example array is\n" + toStr( table ) );
    
    // your tasks:
    
    // (1) read the adjancency data from the file into an appropriate data structure
    //     remember that you have INF to represent infinity, which is nice!
    // (2) allocate data in which to run FW and track parents
    // (3) implement FW (with parent tracking)
    // (4) adapt the loop below to answer queries about shortest paths
    // (5) [Extra Credit] print the paths, too, from src to dst
    
    // user-interaction loop!
    while (true) 
    {
      pl("\nEnter 0 to quit.\n");
      
      p("From what city (from 1 to " + numcities + ")? ");
      int src = kbd.nextInt();
      if (src == 0) break;
      
      p("  To what city (1-" + numcities + ")? ");
      int dst = kbd.nextInt();
      if (dst == 0) break;
      
      pl("From city # " + src + "\n  to city # " + dst);
      pl("  the minimum cost of a path is " + " [[Not Implemented Yet]]");
      //pl("\nAnd the path is " + "[[Not implemented Yet - Extra Credit]]");
    }
  } 

}