解题思路：

暴力

棋盘类题目取反操作：

f[a][b]^=1; 或者f[a][b] = 1 - f[a][b];

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        int m = scan.nextInt();

        int[][] f = new int[n][n];
        for (int i = 0; i < m; i++) {
            int x1 = scan.nextInt();
            int y1 = scan.nextInt();
            int x2 = scan.nextInt();
            int y2 = scan.nextInt();

            for (int a = x1 - 1; a < x2; a++) {
                for (int b = y1 - 1; b < y2; b++) {
                    f[a][b] ^= 1;
                }
            }
        }
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                System.out.print(f[i][j]);
                if ((j + 1) == n)
                    System.out.println();
            }
        }
    }
}