Given a positive integer n, generate a square matrix filled with elements from 1 to n^2 in spiral order.
（螺旋式生成矩阵）
Example:
1. 方向模拟
事先定义四个方向，按照题中的螺旋式的方向在遍历矩阵，过程中遇到边界时不断的修改方向并修改新的边界。具体实现过程如下：
（与Spiral Matrix类似）
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
class :
def generateMatrix(self, n):
"""
:type n: int
:rtype: List[List[int]]
"""
if n == 0:
return []
direct_map = {
'right': [0, 1],
'down': [1, 0],
'left': [0, -1],
'up': [-1, 0]
}
result = [[0]*n for _ in range(n)]
left_border, right_border, up_border, down_border=0, n-1, 0, n-1
fill = 1
direction = 'right'
i, j = 0, 0
while fill <= n*n:
result[i][j] = fill
fill += 1
if direction=='right' and j==right_border:
direction = 'down'
up_border += 1
elif direction=='down' and i==down_border:
direction='left'
right_border -= 1
elif direction=='left' and j==left_border:
direction='up'
down_border -= 1
elif direction=='up' and i==up_border:
direction='right'
left_border += 1
i += direct_map[direction][0]
j += direct_map[direction][1]
return result
|
近期评论