【LeetCode】867. Transpose Matrix 转置矩阵（Easy）（JAVA）
题目地址: https://leetcode.com/problems/transpose-matrix/
题目描述：
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.
Example 1:
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [[1,4,7],[2,5,8],[3,6,9]]
Example 2:
Input: matrix = [[1,2,3],[4,5,6]]
Output: [[1,4],[2,5],[3,6]]
Constraints:
- m == matrix.length
- n == matrix[i].length
- 1 <= m, n <= 1000
- 1 <= m * n <= 10^5
- -10^9 <= matrix[i][j] <= 10^9
题目大意
给你一个二维整数数组 matrix， 返回 matrix 的 转置矩阵 。
矩阵的 转置 是指将矩阵的主对角线翻转，交换矩阵的行索引与列索引。
解题方法
- 遍历二维数组，然后交换行和列的位置即可
class Solution {
public int[][] transpose(int[][] matrix) {
if (matrix.length == 0 || matrix[0].length == 0) return matrix;
int[][] res = new int[matrix[0].length][matrix.length];
for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix[i].length; j++) {
res[j][i] = matrix[i][j];
}
}
return res;
}
}
执行耗时:1 ms,击败了38.35% 的Java用户
内存消耗:39.4 MB,击败了43.95% 的Java用户
