LeetCode: 868. 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

解题思路

根据矩阵转置的定义，将原矩阵行列互换。

AC 代码

class Solution {
public:
    vector<vector<int>> transpose(vector<vector<int>>& A) {
        if(A.empty()) return{{}};

        vector<vector<int>> ans;

        for(size_t i = 0; i < A[0].size(); ++i)
        {
            vector<int> line;
            for(size_t j = 0; j < A.size(); ++j)
            {
                line.push_back(A[j][i]);
            }

            ans.push_back(line);
        }

        return ans;
    }
};