SpiralMatrix

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class SpiralMatrixBuilder {
    static void fillRight(int[][] matrix, int row, int col, int fill) {
        while (matrix[row][col + 1] != 0 && col + 1 < matrix[0].length) {
            matrix[row][col + 1] = fill;
            fill++;
            col++;
        }
    }
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        int [][] matrix = new int[n][n];
        fillSpiral(matrix, 0, 0);
        printMatrix(matrix);
    }
    static int fill = 1;
    static void fillSpiral(int[][] matrix, int x, int y) {
        if (x >= matrix.length || y >= matrix[0].length || y < 0) return;
        if(matrix[x][y] != 0 ) return;
        matrix[x][y] = fill;
        fill ++;
        fillSpiral(matrix, x, y + 1);

        printMatrix(matrix);
        System.out.println();

        fillSpiral(matrix, x + 1, y);

        printMatrix(matrix);
        System.out.println();

        fillSpiral(matrix, x, y - 1);

        printMatrix(matrix);
        System.out.println();

        fillSpiral(matrix, x - 1, y);

        printMatrix(matrix);
        System.out.println();
    }
    static void printMatrix(int[][] matr) {
        for (int i = 0; i < matr.length; i++) {
            for (int j = 0; j < matr[0].length; j++) {
                System.out.print(matr[i][j]);
            }
            System.out.println();
        }
    }
}