Transpose Matrix LT867

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. 1 <= A.length <= 1000
2. 1 <= A[0].length <= 1000

 Idea 1. Transpose, M * N -> N * M, A[i][j] -> result[j][i], copy directly

Time complexity: O(M*N)

Space complexity: O(M*N)

class Solution {
    public int[][] transpose(int[][] A) {
        int m = A.length; 
        int n = A[0].length;
        int[][] result = new int[n][m];
        
        for(int i = 0; i < m; ++i) {
            for(int j = 0; j < n; ++j) {
                result[j][i] = A[i][j];
            }
        }
        
        return result;
    }
}