Q867 Transpose Matrix

Transpose Matrix

Question

Given a matrix A, return the transpose of A.

The transpose of a matrix is the matrix flipped over it's main diagonal, switching the row and column indices of the matrix.

Example 1:

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

Example 2:

Input: [[1,2,3],[4,5,6]] Output: [[1,4],[2,5],[3,6]]

Note:

• 1 <= A.length <= 1000
• 1 <= A[0].length <= 1000

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Approach 1: Copy Directly

Intuition and Algorithm

The transpose of a matrix A with dimensions R x C is a matrix ans with dimensions C x R for which ans[c][r] = A[r][c].

Let's initialize a new matrix ans representing the answer. Then, we'll copy each entry of the matrix as appropriate.

class Solution:
    def transpose(self, A):
        res = []
        for i in range(len(A[0])):
            temp = []
            for j in range(len(A)):
                temp.append(A[j][i])
            res.append(temp)
        return res

def main():
    A = [[1,2,3],[4,5,6],[7,8,9],[10,11,12]]
    answer=Solution()
    results=answer.transpose(A)
    print(results)


if __name__ == "__main__":
    main()