面试29题:
题目:顺时针打印矩阵(同LeetCode 螺旋矩阵打印)
题: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.
解题思路一:
class Solution:
def printMatrix(self, matrix):
# write code here
if not matrix or len(matrix)<=0 or len(matrix[0])<=0:
return
start=0
rows=len(matrix)
columns=len(matrix[0])
res=[]
while(columns>start*2 and rows>start*2):
self.printMatrixInCircle(matrix,columns,rows,start,res)
start += 1
return res
def printMatrixInCircle(self,matrix,columns,rows,start,res):
endX=columns-1-start
endY=rows-1-start
# 从左到右打印一行
for i in range(start,endX+1):
res.append(matrix[start][i])
# 从上到下打印一列
if start<endY:
for i in range(start+1,endY+1):
res.append(matrix[i][endX])
# 从右到左打印一行
if start<endX and start<endY:
for i in range(endX-1,start-1,-1):
res.append(matrix[endY][i])
# 从下到上打印一列
if start<endX and start<endY-1:
for i in range(endY-1,start,-1):
res.append(matrix[i][start])
解题思路二:
class Solution:
# matrix类型为二维列表,需要返回列表
def printMatrix(self, matrix):
# write code here
return matrix and list(matrix.pop(0))+self.printMatrix(zip(*matrix)[::-1])