public static Node[][] initGraph(int a, int b) {
        Node[][] graph = new Node[a+1][b+1];

        for (int i = 0; i < graph.length; i++) {
            for (int j = 0; j < graph[i].length; j++) {
                graph[i][j] = new Node(i, j);
            }
        }

        for (int i = 1; i < graph.length - 1; i++) {
            for (int j = 0; j < graph[i].length; j++) {
                graph[i][j].edges.add(graph[i+1][j]);
                graph[i][j].edges.add(graph[i-1][j]);
                if (j == 0) graph[i][j].edges.add(graph[i][j+1]);
                else if (j == graph[i].length - 1) graph[i][j].edges.add(graph[i][j-1]);
                else {
                    graph[i][j].edges.add(graph[i][j-1]);
                    graph[i][j].edges.add(graph[i][j+1]);
                }
            }
        }

        int i = 0;

        for (int j = 0; j < graph[i].length; j++) {
            graph[i][j].edges.add(graph[i+1][j]);
            if (j == 0) graph[i][j].edges.add(graph[i][j+1]);
            else if (j == graph[i].length - 1) graph[i][j].edges.add(graph[i][j-1]);
            else {
                graph[i][j].edges.add(graph[i][j-1]);
                graph[i][j].edges.add(graph[i][j+1]);
            }
        }

        i = graph.length - 1;

        for (int j = 0; j < graph[graph.length - 1].length; j++) {
            graph[i][j].edges.add(graph[i-1][j]);
            if (j == 0) graph[i][j].edges.add(graph[i][j+1]);
            else if (j == graph[i].length - 1) graph[i][j].edges.add(graph[i][j-1]);
            else {
                graph[i][j].edges.add(graph[i][j-1]);
                graph[i][j].edges.add(graph[i][j+1]);
            }
        }

        return graph;
    }