LeetCode (867) - Transpose matrix

topic

867. Transpose matrix
gives you a two-dimensional integer array matrix, and returns the transposed matrix of 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.

Example 1:

输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
输出：[[1,4,7],[2,5,8],[3,6,9]]

Example 2:

输入：matrix = [[1,2,3],[4,5,6]]
输出：[[1,4],[2,5],[3,6]]

prompt:

m == matrix.length
n == matrix[i].length
1 <= m, n <= 1000
1 <= m * n <= 105
-109 <= matrix[i][j] <= 109

Solution (Java)

Index transformation of transposed matrix: (i,j) ->(j,i)

class Solution 
{
    
    
    public int[][] transpose(int[][] matrix)
    {
    
    
        int[][] result = new int[matrix[0].length][matrix.length];
        //利用索引变换公式(i,j)->(j,i)
        for(int index = 0;index < matrix.length;index++)
        {
    
    
            for(int scan = 0;scan < matrix[index].length;scan++)
            {
    
    
                result[scan][index] = matrix[index][scan];
            }
        }
        return result;
    }
}