Reshape the Matrix

566. Reshape the Matrix

Difficulty: Easy

Related Topics: Array, Matrix, Simulation

In MATLAB, there is a handy function called reshape which can reshape an m x n matrix into a new one with a different size r x c keeping its original data.

You are given an m x n matrix mat and two integers r and c representing the number of rows and the number of columns of the wanted reshaped matrix.

The reshaped matrix should be filled with all the elements of the original matrix in the same row-traversing order as they were.

If the reshape operation with given parameters is possible and legal, output the new reshaped matrix; Otherwise, output the original matrix.

Example 1:

Input: mat = [[1,2],[3,4]], r = 1, c = 4 Output: [[1,2,3,4]]

Example 2:

Input: mat = [[1,2],[3,4]], r = 2, c = 4 Output: [[1,2],[3,4]]

Code:

class Solution:
    def matrixReshape(self, mat: List[List[int]], r: int, c: int) -> List[List[int]]:
        nums = []
        new_mat = []
        for row in mat:
            for num in row:
                nums.append(num)
                
        if r * c != len(nums): 
            return mat
        else:
            for row_index in range(r):
                new_mat.append(nums[row_index * c : row_index * c + c])
            return new_mat

Feedbacks:

I first put all the elemtns in matrix into single list. Then if row times column not equals to total number of elemtns, I returned original matrix. If not, I made a new matrix based on r and c using slicing. And returned it. Compared to other codes using deque, this code is bit slower.