867. Transpose Matrix

Question

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.

Solution

记录一个新数组res[][]。

双重循环，交换下标将matrix[i][j]复制到res[j][i]，最后返回。

Code

class Solution {
    public int[][] transpose(int[][] matrix) {
        int[][] res = new int[matrix[0].length][matrix.length];
        for(int i = 0; i < matrix.length; i++){
            for(int j = 0; j < matrix[0].length; j++){
                res[j][i] = matrix[i][j];
            }
        }
        return res;
    }
}