簡易版本_八皇后問題_使用回溯法(backtracking)

EightQueensPuzzle.java

package LinkedList;

/*
 * 八皇后問題
 * 此程式用來描述 回溯法(backtracking)
 * 並且修改題目先以四皇后進行解題
 */
public class EightQueensPuzzle {
  public static void main(String[] args) {
    new EightQueensPuzzle();
  }

  public EightQueensPuzzle() {
    int total = 4;//皇后數量
    int maxColumn = total;

    for (int row = 0; row < maxColumn; row++) {
      for (int row2 = 0; row2 < maxColumn; row2++) {
        if (isError(row, row2, 1)) {
          continue;
        }
        for (int row3 = 0; row3 < maxColumn; row3++) {
          if (isError(row2, row3, 1)) {
            continue;
          }
          if (isError(row, row3, 2)) {
            continue;
          }
          for (int row4 = 0; row4 < maxColumn; row4++) {
            if (isError(row3, row4, 1)) {
              continue;
            }
            if (isError(row2, row4, 2)) {
              continue;
            }
            if (isError(row, row4, 3)) {
              continue;
            }
            System.out.println((row + 1) + "," + (row2 + 1) + "," + (row3 + 1) + "," + (row4 + 1));
          }
        }
      }
    }
  }

  private boolean isError(int row, int row2, int space) {
    boolean error = false;
    if (row == row2) {
      error = true;
    } else if (row == row2 + space) {
      error = true;
    } else if (row == row2 - space) {
      error = true;
    }
    return error;
  }
}