867. Transpose Matrix*

867. Transpose Matrix*

​​https://leetcode.com/problems/transpose-matrix/​​

题目描述

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​​

C++ 实现 1

矩阵转置. 注意矩阵 ​​A​​ 行列大小不一定相等 ????

class Solution {
public:
    vector<vector<int>> transpose(vector<vector<int>>& A) {
        if (A.empty() || A[0].empty()) return {};
        int m = A.size(), n = A[0].size();
        vector<vector<int>> res(n, vector<int>(m));
        for (int i = 0; i < m; ++i)
            for (int j = 0; j < n; ++j)
                res[j][i] = A[i][j];
        return res;
    }
};