题目描述
输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字，例如，如果输入如下4 X 4矩阵： 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.
思路
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
用一个bool数组标记走过的路，到底了就按照 右→下→左→上→右 的方式修改运动方向。
def printMatrix(matrix):
# write code here
walked = [[False] * (len(matrix[0])+1) for _ in range(len(matrix)+1)]
for j in range(len(walked[-1])):
walked[-1][j] = True
for i in range(len(walked)):
walked[i][-1] = True
len_row = len(matrix) - 1
len_col = len(matrix[0]) - 1
res = []
i = 0
j = 0
direction = 0 # 0向右，1向下，2向左，3向上
while not walked[i][j]:
res.append(matrix[i][j])
walked[i][j] = True
if direction == 0: # right
if j < len_col and not walked[i][j+1]:
j += 1
else:
direction = 1
i += 1
elif direction == 1: # down
if i < len_row and not walked[i+1][j]:
i += 1
else:
direction = 2
j -= 1
elif direction == 2: # left
if j > 0 and not walked[i][j-1]:
j -= 1
else:
direction = 3
i -= 1
elif direction == 3: # up
if i > 0 and not walked[i-1][j]:
i -= 1