import org.junit.Test;
//回溯法求解
public class QueenFind {public static final int N = 8;public static int count = 0;@Testpublic void test() {int[][] arr = new int[8][8];for (int i = 0; i < N; i++) {for (int j = 0; j < N; j++) {arr[i][j] = 0;}}findQueen(0, arr);System.out.println("count" + count);}public void findQueen(int row, int[][] arr) {if (row == N) {count++;System.out.println("count" + count);return;}for (int i = 0; i < N; i++) {for (int j = 0; j < N; j++) {arr[row][j] = 0;}arr[row][i] = 1;for (int k = 0; k < N; k++) {System.out.print(arr[row][k] + " ");}System.out.println();System.out.println(row);if (isSafety(arr, row, i)) {findQueen(row + 1, arr);}}}private boolean isSafety(int[][] chess, int row, int col) {// 判断中上、左上、右上是否安全int step = 1;while (row - step >= 0) {if (chess[row - step][col] == 1) // 中上return false;if (col - step >= 0 && chess[row - step][col - step] == 1) // 左上return false;if (col + step < N && chess[row - step][col + step] == 1) // 右上return false;step++;}return true;}
}