I'm trying to create an optimal path to collect as many 1's as I can but after I execute my code, I still have an arrow pointing to nothing as there are no more places to go. How would I remove the arrow at the end of the code?

import java.util.Arrays;
import java.util.Scanner;

public class Main{
  public static void main(String[] args){
    Scanner s1 = new Scanner(System.in);
    int n = s1.nextInt();
    int m = s1.nextInt();
    int mat[][] = new int[n][m];
    for (int i = 0; i < mat.length; i  ){
      for (int j = 0; j < mat[0].length; j  ){
        mat[i][j] = s1.nextInt();
      } 
    }
    int path[][] = new int[n][m];
    for (int i = 0; i < path.length; i  ){
      Arrays.fill(path[i], -1);
    }
      
    int maxCoins = util(0, 0, mat, path);
    System.out.println("Max coins:"   maxCoins);
      
    int row = 0, column = 0;
    System.out.print("Path:");
     
    while(row < mat.length && column < mat[0].length){
      System.out.print("("   (row   1)   ","   (column   1)   ")");
      System.out.print("->");
      
      if(row < n - 1 && column < m - 1){
        int down = path[row   1][column];
        int right = path[row][column   1];
        if(down > right){
          row  = 1;
          continue;
        }
        else if (right > down){
          column  = 1;
          continue;
        }
        else{
          row  = 1;
          continue;
        }
      }
      if(row   1 < n){
        row  = 1;
      }
      else{
        column  = 1;
      }
    }
  }
  
  private static int util(int row,int column,int mat[][], int path[][]){
    if(row >= mat.length || column >= mat[0].length){
      return 0;
    }
    
    if(path[row][column]!= -1){
      return path[row][column];
    }
    
    int right = util(row, column   1, mat,path);
    int down = util(row   1, column, mat,path);
    
    path[row][column]=Math.max(right, down);
    if(mat[row][column] == 1){
      path[row][column]  = 1;
    }
    
    return path[row][column];
  }
}

My current input looks like:

5 6
0 0 0 0 1 0
0 1 0 1 0 0
0 0 0 1 0 1
0 0 1 0 0 1
1 0 0 0 1 0

And output is:

Max coins:5
Path:(1,1)->(2,1)->(2,2)->(2,3)->(2,4)->(3,4)->(3,5)->(3,6)->(4,6)->(5,6)->

I am just trying to remove the one at the end but unsure where to insert my code:

System.out.print("->");

Thanks in advance!

CodePudding user response：

Three solutions that come to mind:

1. Add another check inside the loop, and put your sysout -> thingy after that check.
2. Usually code would generate some kind of list or similar data about the results and return it. It's a lot more simple ways to print lists, because you know the length etc.
3. Another common solution is to use StringBuilder and correct it before generating the outout with toString()

CodePudding user response：

Cleanest way would be using a StringJoiner. You can use it as follows

StringJoiner joiner = new StringJoiner("->");
joiner.add("a");
joiner.add("b");
System.out.println(joiner); //prints a->b - you can use toString if you want to return a joined String

You can also define a prefix and suffix for your joined String.

Or if you are familiar with Streams, there is Collectors.joining("->") available.

CodePudding user response：

You could just do something like this:

if (!(row == mat.length - 1 && column == mat[0].length - 1)) {
    System.out.print("->");
}

Or a little cleaner:

if (arrowIsNotAtTheEnd(mat, row, column)) {
    System.out.print("->");
}

// ...

private static boolean arrowIsNotAtTheEnd(int[][] mat, int row, int column) {
    return !(row == mat.length - 1 && column == mat[0].length - 1);
}