aoc21 15A broken

import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashMap;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Scanner;

public class Solution15A {
  public static int[][] dirs = {{-1,0}, {1,0}, {0,-1}, {0,1}};
  public static int key(int x, int y) {
    return (y<<16)|x;
  }
  public static class Node implements Comparable<Node> {
    public int x;
    public int y;
    public int w;
    public int c;
    public int compareTo(Node n) {
      return this.c-n.c;
    }
  }
  public static void main(String[] args) {
    PriorityQueue<Node> q = new PriorityQueue<>();
    Map<Integer, Node> m = new HashMap<>();
    int x = 0, y = 0;
    try {
      File myObj = new File(args[0]);
      Scanner myReader = new Scanner(myObj);
      while (myReader.hasNextLine()) {
        String data = myReader.nextLine();
        for (x = 0; x < data.length(); x++) {
          Node n = new Node();
          n.x = x;
          n.y = y;
          n.w = data.charAt(x)-'0';
          n.c = Integer.MAX_VALUE;
          m.put(key(x, y), n);
          q.offer(n);
        }
        y++;
      }
      myReader.close();
    } catch (FileNotFoundException e) {
      System.out.println("An error occurred.");
      e.printStackTrace();
    }
    Node start = m.get(key(0, 0));
    Node end = m.get(key(x-1, y-1));
    q.remove(start);
    start.c = 0;
    q.offer(start);
    if (q.peek() != start) System.out.println("An error occurred.");
    while (!q.isEmpty()) {
      Node n = q.poll();
      if (n == end) break;
      m.remove(n);
      for (int[] dir : dirs) {
        Node o = m.get(key(n.x+dir[0], n.y+dir[1]));
        if (o != null && o.c > n.w+n.c) {
          q.remove(o);
          o.c = n.w+n.c;
          q.offer(o);
        }
      }
    }
    System.out.println(end.c);
  }
}