You are given an n x n square matrix of integers grid. Return the matrix such that:
- The diagonals in the bottom-left triangle (including the middle diagonal) are sorted in non-increasing order.
- The diagonals in the top-right triangle are sorted in non-decreasing order.
Examples
Example 1
Input: grid = [[1,7,3],[9,8,2],[4,5,6]]
Output: [[8,2,3],[9,6,7],[4,5,1]]
The diagonals with a black arrow (bottom-left triangle) should be sorted in non-increasing order: [1, 8, 6] becomes [8, 6, 1]. [9, 5] and [4] remain unchanged. The diagonals with a blue arrow (top-right triangle) should be sorted in non-decreasing order: [7, 2] becomes [2, 7]. [3] remains unchanged.
Example 2
Input: grid = [[0,1],[1,2]]
Output: [[2,1],[1,0]]
The diagonals with a black arrow must be non-increasing, so [0, 2] is changed to [2, 0]. The other diagonals are already in the correct order.
Example 3
Input: grid = [[1]]
Output: [[1]]
Diagonals with exactly one element are already in order, so no changes are needed.
Constraints
grid.length == grid[i].length == n1 <= n <= 10-10⁵ <= grid[i][j] <= 10⁵