[Leetcode] 867. Transpose-matrix (simulation) [simple]

link

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

time consuming

Problem solving: 4 min
Problem solving: 4 min

Title

Gives you a two-dimensional integer array matrix, and returns the transposed matrix of the matrix.

The transposition of a matrix refers to flipping the main diagonal of the matrix and exchanging the row index and column index of the matrix.

prompt:

• m == matrix.length
• n == matrix[i].length
• 1 <= m, n <= 1000
• 1 <= m * n <= 10^5
• -10^9 <= matrix[i][j] <= 10^9

Ideas

According to the definition of the transpose matrix-exchange row and column index, see the code for details.

Time complexity: $O(m\ast n)$

AC code

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