867. Transpose Matrix

Given a 2D integer array matrix, return the transpose of matrix.

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

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