Question

我几乎完成了代码，其中方法返回具有相同元素的对象的最长序列。如果我的2D ArrayList myBoard看起来像这样：

    |  0|  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11|
    +---+---+---+---+---+---+---+---+---+---+---+---+
  0 | 11| 11| 12| 12| 12| 12| 12| 12| 12| 12| 12| 12|
    +---+---+---+---+---+---+---+---+---+---+---+---+
  1 |  o|  o|  o|  ~|  ~|  ~|  ~|  ~|  ~|  ~|  ~|  ~|
    +---+---+---+---+---+---+---+---+---+---+---+---+
  2 |  b|  b|  b|  b|  ~|  ~|  ~|  ~|  ~|  ~|  ~|  ~|
    +---+---+---+---+---+---+---+---+---+---+---+---+
  3 | 11| 11| 11| 11| 11| 11|  ~|  ~|  ~|  ~|  ~|  ~|
    +---+---+---+---+---+---+---+---+---+---+---+---+
  4 |  b|  b|  b|  b|  ~|  ~|  ~|  ~|  ~|  ~|  ~|  ~|
    +---+---+---+---+---+---+---+---+---+---+---+---+
  5 | 11| 11| 12| 12| 12|500| 12|480| 12| 12| 12| 12|
    +---+---+---+---+---+---+---+---+---+---+---+---+

然后方法longestHorizontalSequence（）应该返回

[(0,2,12), (0,3,12), (0,4,12), (0,5,12), (0,6,12), (0,7,12),....(0,11,12)]

但我的方法返回：

[(0,0,11), (0,1,11), (0,2,12), (0,3,12), (0,4,12), (0,5,12), (0,6,12), (0,7,12),.....,(0,11,12)]

即。它返回整行的最长序列。我试过调试但无法猜测我的代码应该改变什么。请问smb请看一下？提前谢谢！

public List<RowColElem<T>> getHorizontalSequence(ArrayList<ArrayList<T>> myBoard){
     ArrayList<RowColElem<T>> result = new ArrayList<RowColElem<T>>();

     int count = 1;
     int max = 1;
     int row1 = 0;
     int col1 = 0;
     for(int i = minRow; i <= maxRow; i++){


         List<RowColElem<T>> currentList = new ArrayList<RowColElem<T>>();
         RowColElem<T> obj = new RowColElem<T>(i, minRow, myBoard.get(i-minRow).get(0));
         T elem = obj.getElem();
         currentList.add(obj);

         for(int j = minCol + 1; j <= maxCol; j++){

             row1 = i - minRow;
             col1 = j - minCol;
             if(elem.equals(myBoard.get(row1).get(col1)) 
                     && (!(elem.equals(this.element))) 
                     && (!(myBoard.get(row1).get(col1).equals(this.element)))){


                 count++;
                 RowColElem<T> obj1 = new RowColElem<T>(i,j, myBoard.get(row1).get(col1));
                 currentList.add(obj1);
                 obj = new RowColElem<T>(i, j, myBoard.get(row1).get(col1));

                 if(count > max){
                     max = count;
                    /* while(max != 0){
                         currentList.remove(max--);
                     }*/
                 }

                 if(currentList.size() > result.size()){
                     result.clear();
                     result.addAll(currentList);
                 }
             }

             else{

                 if(obj.getElem().equals(this.element)){
                     currentList.remove(0);
                 }
                 elem = myBoard.get(row1).get(col1);
                 obj = new RowColElem<T>(i,j, elem);
                 currentList.add(obj);

                 count = 1;

             }
         }
     }
     return result;
}

班级**RowColElem**

public class RowColElem<T>{

    private int row;
    private int col;
    private T e;

    // Create a RowColElem with the parameter parts
    public RowColElem(int r, int c, T e){
        this.row = r;
        this.col = c;
        this.e = e;
    }

    // Return the row
    public int getRow(){
        return this.row;
    }

    // Return the column
    public int getCol(){
        return this.col;
    }

    // Return the element
    public T getElem(){
        return this.e;
    }

    // Return a pretty string version of the triple formated as
    // (row,col,elem)
    public String toString(){
        return "(" + this.row + "," + this.col + "," + this.e.toString() + ")";
    }
}

Answer 1

而不是：

else{

             if(obj.getElem().equals(this.element)){
                 currentList.remove(0);
             }
             elem = myBoard.get(row1).get(col1);
             obj = new RowColElem<T>(i,j, elem);
             currentList.add(obj);

             count = 1;

         }

尝试：

else{
             currentList.clear();
             elem = myBoard.get(row1).get(col1);
             obj = new RowColElem<T>(i,j, elem);
             currentList.add(obj);

             count = 1;

         }

如果我是正确的，你没有正确清除你的currentList arraylist，所以它保持整行，而不是你想要的那一组。

或者，放弃整个RowColElem类并简单地跟踪每个位置的起始位置和最长水平序列将更简单。它可以很容易地在2个for循环中完成，每当左边的对象等于当前对象时，你递增最长的子序列变量。每次向前移动时，请检查该号码是否为＆gt; max，因此存储序列的起始位置和当前位置（序列的结尾）。

从2D Arraylist获取最长序列时出错

1 个答案: