Rotate Matrix in Python

Python Server Side Programming Programming

Suppose we have one n x n 2D matrix. We have to rotate this matrix 90 degrees clockwise. So if the matrix is like-

1	5	7
9	6	3
2	1	3

Then the output will be

2	9	1
1	6	5
3	3	7

To solve this, we will follow these steps −

Consider temp_mat = [], col := length of matrix – 1
for col in range 0 to length of matrix
- temp := []
- for row in range length of matrix – 1 down to -1
  - add matrix[row, col] in temp
- add temp into temp_mat
for i in range 0 to length of matrix
- for j in range 0 to length of matrix
  - matrix[i, j] := temp_mat[i, j]

Let us see the following implementation to get better understanding −

Example Code (Python)

Live Demo

class Solution(object):
   def rotate(self, matrix):
      temp_matrix = []
      column = len(matrix)-1
      for column in range(len(matrix)):
         temp = []
         for row in range(len(matrix)-1,-1,-1):
            temp.append(matrix[row][column])
         temp_matrix.append(temp)
      for i in range(len(matrix)):
         for j in range(len(matrix)):
            matrix[i][j] = temp_matrix[i][j]
      return matrix

ob1 = Solution()
print(ob1.rotate([[1,5,7],[9,6,3],[2,1,3]]))

Input

[[1,5,7],[9,6,3],[2,1,3]]

Output

[[2, 9, 1], [1, 6, 5], [3, 3, 7]]

Arnab Chakraborty

Published on 05-Jan-2021 07:04:02

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