867. Transpose Matrix

Problem:

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

思路：

Solution (C++):

vector<vector<int>> transpose(vector<vector<int>>& A) {
    int m = A.size(), n = A[0].size();
    vector<vector<int>> res(n, vector<int>(m, 0));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j)
            res[i][j] = A[j][i];
    }
    return res;
}

性能：

Runtime: 28 ms  Memory Usage: 9.1 MB

思路：

Solution (C++):

性能：

Runtime: ms  Memory Usage: MB