Python3求解旋转矩阵问题
原题 https://leetcode-cn.com/problems/spiral-matrix/
给定一个包含 m x n 个元素的矩阵(m 行, n 列),请按照顺时针螺旋顺序,返回矩阵中的所有元素。
示例 1:
输入:
[
[ 1, 2, 3 ],
[ 4, 5, 6 ],
[ 7, 8, 9 ]
]
输出: [1,2,3,6,9,8,7,4,5]
示例 2:
输入:
[
[1, 2, 3, 4],
[5, 6, 7, 8],
[9,10,11,12]
]
输出: [1,2,3,4,8,12,11,10,9,5,6,7]
解题:
class Solution:
def spiralOrder(self, matrix: List[List[int]]) -> List[int]:
m = len(matrix)
if m == 0:
return []
n = len(matrix[0])
if n == 0:
return 0
res = []
dir = 1 # 方向:1 右 2 下 3 左 4 上
x = 0 # 起始列标
y = 0 # 起始行标
while True:
if x == -1 or x == n or y == -1 or y == m or matrix[y][x] == None:
break
res.append(matrix[y][x])
matrix[y][x] = None
if dir == 1 and ( x + 1 == n or matrix[y][x + 1] == None):
dir = 2
elif dir == 2 and (y + 1 == m or matrix[y + 1][x] == None):
dir = 3
elif dir == 3 and (x - 1 == -1 or matrix[y][x - 1] == None):
dir = 4
elif dir == 4 and (y - 1 == -1 or matrix[y - 1][x] == None):
dir = 1
if dir == 1:
x += 1
elif dir == 2:
y += 1
elif dir == 3:
x -= 1
elif dir == 4:
y -= 1
return res