package eightQuen;

/**
 * 八皇后問題
 * 
 * @author 83771
 *
 */
public class eight {
  // 定義一個數(shù)組 表示棋盤
  public static Integer[][] checkerBoard = new Integer[8][8];
  // 棋盤副本
  public static Integer[][] checkerBoardCopy = new Integer[8][8];

  // 計數(shù)器 用于計數(shù)有多少種方法
  public static Integer jishu = 1;

  // 定義橫豎斜方向上是否有棋子
  public static boolean flag1 = true;
  public static boolean flag2 = true;
  public static boolean flag3 = true;
  public static boolean flag4 = true;

  // 初始化一個棋盤 8x8
  public static void init() {
    for (int i = 0; i < 8; i++) {
      for (int j = 0; j < 8; j++) {
        System.out.print(0 + "  ");
        checkerBoard[i][j] = 0;
      }
      System.out.println();
    }
    checkerBoardCopy = checkerBoard;
  }

  // 遞歸測試方法
  public static void startTest(int row) {
    for (int col = 0; col < 8; col++) {
      if (checkCheet(row, col, checkerBoardCopy) == 1) {
        if (row < 7) {
          startTest(++row);
          --row;
        }
      }
      // 該行重新賦值為0  進(jìn)行下一次判斷
      checkerBoardCopy[row][col] = 0;
    }
  }

  // 檢查是否危險
  // row行
  // col列
  public static int checkCheet(int row, int col, Integer[][] checkerBoardCopy) {
    flag1 = true;
    flag2 = true;
    flag3 = true;
    flag4 = true;
    // 行方向上是否滿足條件
    for (int i = 0; i < 8; i++) {
      if (checkerBoardCopy[row][i] == 1) {
        flag1 = false;
        break;
      }
    }
    // 列方向上是否滿足條件
    for (int j = 0; j < 8; j++) {
      if (checkerBoardCopy[j][col] == 1) {
        flag2 = false;
        break;
      }
    }
    // 右下方向
    for (int i = row, j = col; i < 8 & j < 8; i++, j++) {
      if (checkerBoardCopy[i][j] == 1) {
        flag3 = false;
        break;
      }
    }
    // 左上方向
    for (int i = row, j = col; i >= 0 & j >= 0; i--, j--) {
      if (checkerBoardCopy[i][j] == 1) {
        flag3 = false;
        break;
      }
    }
    // 左下方向
    for (int i = row, j = col; i < 8 & j >= 0; i++, j--) {
      if (checkerBoardCopy[i][j] == 1) {
        flag4 = false;
        break;
      }
    }
    // 右上方向
    for (int i = row, j = col; i >= 0 & j < 8; i--, j++) {
      if (checkerBoardCopy[i][j] == 1) {
        flag4 = false;
        break;
      }
    }
    if (flag1 & flag2 & flag3 & flag4) {
      // 若為真 增此點的值賦為1
      checkerBoardCopy[row][col] = 1;
      // 如果已經(jīng)判斷到最后一行 并且最后一行也符合情況 打印整個棋盤
      if (row == 7) {
        printCheets(checkerBoardCopy);
      }
      return 1;
    }
    return 0;
  }

  // 打印棋盤方法
  public static void printCheets(Integer[][] checkerBoardCopy) {
    for (int i = 0; i < 8; i++) {
      for (int j = 0; j < 8; j++) {
        System.out.print(checkerBoardCopy[i][j] + "  ");
      }
      System.out.println();
    }
    System.out.println("=================" + jishu++);
  }

  public static void main(String[] args) {
    init();
    startTest(0);
  }
}