一個有關皇後問題的程序(C#)

using System;
namespace sunjoy
{
 public class Queen
 {
  public static int Main()
  {
   int board_size = 0,x=0,y=0;//棋盤大小,當前行,當前列
   uint solution_count = 0;   //皇後擺放方案的個數
   int[] rows, cols, slot1, slot2, x2y;//行占用情況，列占用情況，“/”狀斜線占用情況，“\”狀斜線占用情況，皇後坐標
   DateTime t_start, t_end;
           
   Console.WriteLine("請輸入棋盤的大小");
   try
   {
    board_size = Convert.ToInt32(Console.ReadLine());
    if (board_size <= 0)
    {
     Console.WriteLine("非法數據");
     return -1;
    }
   }
   catch (Exception e) { Console.WriteLine("發生異常" + e.Message); };

   rows = new int[board_size];
   cols = new int[board_size];
   slot1 = new int[board_size * 2 - 1];
   slot2 = new int[board_size * 2 - 1];
   x2y = new int[board_size];

   for (int i = 0; i < board_size; i++)
    x2y[i] = -1;   //坐標初始化都為-1
   t_start = DateTime.Now;
   while (true)
   {
    for (y = x2y[x]+1; y < board_size; y++)
     if (rows[x] == 0 && cols[y] == 0 && slot1[x + y] == 0 && slot2[x - y + board_size - 1] == 0)
      break;

    if (y < board_size)
    {
     //第X行的棋子落下
     rows[x] = 1; cols[y] = 1; slot1[x + y] = 1; slot2[x - y + board_size - 1] = 1; x2y[x] = y;
    }  
    else
    {
     //回溯，