打印蛇形排列的数（这算法挺牛的）

class
 snakePrint {
    static
 
int
 length = 
7
;
    static
 
int
 value = 
1
;
    static
 
int
[][] snake = 
new
 
int
[length][length];
    static
 Direction lastDirection = Direction.Right;

    static
 
enum
 Direction {
        Right, Down, Left, Up;
    }

    public
 
static
 
void
 initialArray() {
        int
 row = 
0
, line = 
0
;
        for
 (
int
 c = 
0
; c < length * length; c++) {
            snake[row][line] = value;
            lastDirection = findDirection(row, line);
            switch
 (lastDirection) {
                case
 Right:
                    line++;
                    break
;
                case
 Down:
                    row++;
                    break
;
                case
 Left:
                    line--;
                    break
;
                case
 Up:
                    row--;
                    break
;
                default
:
                    System.out.println("error"
);
            }
            value++;
        }
    }

    static
 Direction findDirection(
int
 row, 
int
 line) {
        Direction direction = lastDirection;
        switch
 (direction) {
            case
 Right: {
                if
 ((line == length - 
1
) || (snake[row][line + 
1
] != 
0
))
                    direction = direction.Down;
                break
;
            }
            case
 Down: {
                if
 ((row == length - 
1
) || (snake[row + 
1
][line] != 
0
))
                    direction = direction.Left;
                break
;
            }
            case
 Left: {
                if
 ((line == 
0
) || (snake[row][line - 
1
] != 
0
))
                    direction = direction.Up;
                break
;
            }
            case
 Up: {
                if
 (snake[row - 
1
][line] != 
0
)
                    direction = direction.Right;
                break
;
            }
        }
        return
 direction;
    }

    public
 
static
 
void
 main(String[] args) {
        initialArray();

        // display.....
        for
 (
int
 i = 
0
; i < length; i++) {
            for
 (
int
 j = 
0
; j < length; j++) {
                System.out.print(snake[i][j] + "  "
);
            }
            System.out.println();
        }
    }
}