054-spiral-matrix.py

"""
Problem Link: https://leetcode.com/problems/spiral-matrix/

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

Example 1:
Input:
[
 [ 1, 2, 3 ],
 [ 4, 5, 6 ],
 [ 7, 8, 9 ]
]
Output: [1,2,3,6,9,8,7,4,5]

Example 2:
Input:
[
 [1, 2, 3, 4],
 [5, 6, 7, 8],
 [9,10,11,12]
]
Output: [1,2,3,4,8,12,11,10,9,5,6,7]
"""
classSolution(object):
defspiralOrder(self, matrix):
"""
 :type matrix: List[List[int]]
 :rtype: List[int]
 """
ifmatrix== []:
return []
top=left=0
bottom=len(matrix) -1
right=len(matrix[0]) -1
direction=0
res= []
whiletop<=bottomandleft<=right:
ifdirection==0:
foriinrange(left,right+1):
res.append(matrix[top][i])
top+=1
elifdirection==1:
foriinrange(top,bottom+1):
res.append(matrix[i][right])
right-=1
elifdirection==2:
foriinrange(right,left-1,-1):
res.append(matrix[bottom][i])
bottom-=1
elifdirection==3:
foriinrange(bottom, top-1, -1):
res.append(matrix[i][left])
left+=1
direction= (direction+1) %4
returnres