编辑代码

import java.util.LinkedList;

class Main {


public class Queue {
private static boolean isCorrectColumn(int col, int curRow, int queueCount, int[] path) {
boolean bCorrect = true;
int leftup = col - 1;
int rightup = col + 1;

for (int i = curRow - 1; i >= 0; --i) {
if (path[i] == col) {
//在同一列
bCorrect = false;
break;
}

if (leftup >= 0 && path[i] == leftup) {
//在同一左斜线上
bCorrect = false;
break;
}

if ( rightup < queueCount && path[i] == rightup) {
//在同一右斜线上
bCorrect = false;
break;
}
--leftup;
++rightup;
}

return bCorrect;
}
public static void findQueuePos(int queueCount, int curRow, int[] path, LinkedList<int[]> solutions) {
if (queueCount == curRow) {
solutions.add((int[])path.clone());
return;
}

for (int i = 0; i < queueCount; ++i) {
if (isCorrectColumn(i, curRow, queueCount, path)) {
path[curRow] = i;
findQueuePos(queueCount, curRow + 1, path, solutions);
}
}
}

public static LinkedList<int[]> solveQueueProblem(int queueCount) {
LinkedList<int[]> solutions = new LinkedList<int[]>();
int[] path = new int[queueCount];

findQueuePos(queueCount, 0, path, solutions);
return solutions;
}

public static void printQueueSolutions(int queueCount, LinkedList<int[]> solutions) {
System.out.println("皇后问题有" + solutions.size() + "种解决方案：");
for (int[] solution:solutions) {
for (int i = 0; i < solution.length; ++i) {
for (int j = 0; j < queueCount; ++j) {
if (j == solution[i]) {
System.out.print('O');
}
else {
System.out.print('X');
}
}
System.out.println();
}

System.out.println();
System.out.println();
}
}

public static void test() {
LinkedList<int[]> solutions = solveQueueProblem(4);
printQueueSolutions(4, solutions);
}
}

    public static void main(String[] args) {
Queue.test();
    }
}