Question

这是我在Java中顺时针旋转90度方形矩阵的代码。

import java.util.ArrayList;

public class Main {

    public static void main(String[] args) {
    // write your code here
        int size = 4;
        int[][] matrix = new int[size][size];
        for (int i = 0; i < size ; i++) {
            for (int j = 0; j < size; j++) {

                matrix[i][j] = (i+(2*j));
            }
        }
        trace(matrix, size);
        rotate(matrix);
        System.out.println("________________________");
        trace(matrix, size);

    }

    public static void rotate(int[][] matrix){
        int stop = matrix.length -1;

        rotate(matrix, stop, 0);
    }

    public static void rotate(int[][] matrix, int stop, int start){

        if(start - stop == 1) return;

        ArrayList<Integer> temp = new ArrayList<>();

        //save top row in an array
        for (int i = start; i <= stop ; i++) {
            temp.add(matrix[start][i]);
        }

        //left goes to top
        for (int i = start; i <= stop ; i++) {
            matrix[start][i] = matrix[stop - i][start];
        }

        //bottom goes to left
        for (int i = start; i <= stop ; i++) {
            matrix[i][start] = matrix[stop][i];
        }

        //right goes to bottom
        for (int i = start; i <= stop ; i++) {
            matrix[stop][stop - i] = matrix[i][stop];
        }

        //temp array goes to right
        for (int i = 0; i < temp.size() ; i++) {
            matrix[start + i][stop] = temp.get(i);
        }

        rotate(matrix, stop-1, start + 1);
    }



    public static void trace(int[][] matrix, int size){
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size ; j++) {
                System.out.print(matrix[i][j] + " ");

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

原始数组和输出如下所示，

0 2 4 6 
1 3 5 7 
2 4 6 8 
3 5 7 9 
________________________
3 2 1 0 
5 4 3 2 
6 2 5 4 
3 8 7 6

显然，答案并不完全正确。虽然它几乎就在那里。我对这些错误感到有点迷茫，任何帮助都表示赞赏。

Answer 1

此代码似乎工作正常。这里的测试用例是一个8x8矩阵，可以根据您的测试用例缩放到4x4。

    $qb = $entityManager->createQueryBuilder();
    $qb->select('accident.city')->distinct();
    $qb->from('VisDatasetBundle:Accident','accident');

    $result = $qb->getQuery()->getResult();
    $i = 0;
    $qb->delete();

    while($i < count($result)){

    $qb = $entityManager->createQueryBuilder();
    $qb->select('count(accident.city)');
    $qb->from('VisDatasetBundle:Accident', 'accident');
    $qb->where('accident.city = \'' . $result[$i]['city'] . '\'');
    $count = $qb->getQuery()->getResult();
    $result[$i]['count'] = $count[0]['1'];
    $qb->delete();
        $i++;
    }

    return $result;

}

将方阵旋转90度

1 个答案: