867. Transpose Matrix
EasyLeetCodeGiven 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
1 <= matrix[i][j] <= 10^4
How to solve the problem
- Using nested loop to change row and column.
Code
python
class Solution:
def transpose(self, matrix: List[List[int]]) -> List[List[int]]:
result = [[0] * len(matrix) for _ in range(len(matrix[0]))] #both work
# result = [[0 for _ in range(len(matrix))] for _ in range(len(matrix[0]))] # both work
for i in range(len(matrix)):
for j in range(len(matrix[0])):
result[j][i] = matrix[i][j]
return result
Complexity
Time complexity: O(m*n)
- Outer loop runs m times, inner loop runs n times. So T(n) = O(m*n).
Space complexity: O(m*n)
- Create a new matrix
result
which space is O(m*n)
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