Solution
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.
Complexity Analysis

Time Complexity: , where and are the number of rows and columns in the given matrix
A
. 
Space Complexity: , the space used by the answer.
Analysis written by: @awice.