跟n皇后是一样的思路，不过每行要放两个棋子。黑皇后和白皇后的棋子分开存储就行了。
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;public class Main{private static int n;private static List<int[]> blacks = new ArrayList<>();private static List<int[]> whites = new ArrayList<>();private static int ans;private static int[][] map;public static void main(String[] args){Scanner scanner = new Scanner(System.in);n = scanner.nextInt();map = new int[n][n];for(int i = 0; i < n; i++){for(int j = 0; j < n; j++){map[i][j] = scanner.nextInt();}}scanner.close();dfs(0);System.out.println(ans);}private static boolean isValid(int r, int c, List<int[]> queues){if(map[r][c] == 0) return false;for(int[] queue : queues){int qr = queue[0];int qc = queue[1];if(qc == c) return false;if(r - qr == Math.abs(c - qc)) return false;}return true;}private static void dfs(int row){if(row == n){ans += 1;return;}for(int black = 0; black < n; black++){if(!isValid(row, black, blacks))continue;for(int white = 0; white < n; white++){if(black == white)continue;if(!isValid(row, white, whites))continue;int[] blackQueue = new int[]{row, black};int[] whiteQueue = new int[]{row, white};blacks.add(blackQueue);whites.add(whiteQueue);dfs(row + 1);blacks.remove(blackQueue);whites.remove(whiteQueue);}}}
}