順時針從外往裏打印數字

順時針從外往裏打印數字

參考連接 https://mp.weixin.qq.com/s/nzUTmCuIaSgtpag5S1RQ3w

/**
 * @author lin
 * @date 18/7/27
 * @license Copyright (c) 2016 那鎂克
 */

public class demo {


    public void print(int a[][]) {
        int realRow = a.length;
        int row = realRow / 2;
        if ((realRow&1) == 1) {
            row = row + 1;
        }
        for (int r = 0, c = 0; r < row; r ++, c++) {
            int col = a[r].length;
            int dr = r;
            int dc = c;
            while (dc < c + col - c * 2) {
                System.out.print(a[dr][dc] + " ");
                dc ++;
            }
            dc --;
            dr ++;
            while (dr < r + realRow - r * 2) {
                System.out.print(a[dr][dc] + " ");
                dr ++;
            }
            dr --;
            dc --;
            while (dc >= c) {
                System.out.print(a[dr][dc] + " ");
                dc --;
            }
            dc ++;
            dr --;
            while (dr > r) {
                System.out.print(a[dr][dc] + " ");
                dr --;
            }
        }
    }

    public static void main(String[] args) {

//        int arr[][] = {
//                {1,2,3,4,5},
//                {14,15,16,17,6},
//                {13,20,19,18,7},
//                {12,11,10,9,8}
//        };

        int arr[][] = {
                {1,  2,  3,  4,  5},
                {16, 17, 18, 19, 6},
                {15, 24, 25, 20, 7},
                {14, 23, 22, 21, 8},
                {13, 12, 11, 10, 9}
        };

        demo d = new demo();
        d.print(arr);
    }

}

思路

int arr[][] = {
                {1,  2,  3,  4,  5},
                {16, 17, 18, 19, 6},
                {15, 24, 25, 20, 7},
                {14, 23, 22, 21, 8},
                {13, 12, 11, 10, 9}
        };

對應的索引其實就是:

0 [0, 1, 2, 3, 4]
1 [0,          , 4]
2 [0,         , 4]
3 [0,         , 4]
4 [0, 1, 2, 3, 4]

0 [                ]
1 [ , 1, 2, 3,     ]
2 [, 1, 2, 3      ]
3 [, 1, 2, 3     ]
4 [               ]

裏面至關於又是一個二維數組

這恐怕是最挫的一種寫法了