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 n

sortMatrix.js

/**
 * @param {number[][]} grid
 * @return {number[][]}
 */
var sortMatrix = function(grid) {
    const n = grid.length;

    // Helper to extract a matrix starting at (row, col)
    function getMatrix(row, col) {
        const matrix = [];
        while (row < n && col < n) {
            matrix.push(grid[row][col]);
            row++;
            col++;
        }
        return matrix;
    }

    // Helper to write a sorted matrix back into the grid
    function setMatrix(row, col, sorted) {
        let i = 0;
        while (row < n && col < n) {
            grid[row][col] = sorted[i];
            row++;
            col++;
            i++;
        }
    }

    // Bottom-left triangle (including main matrix)
    for (let row = 0; row < n; row++) {
        const matrix = getMatrix(row, 0);
        matrix.sort((a, b) => b - a); // Descending
        setMatrix(row, 0, matrix);
    }

    // Top-right triangle (excluding main matrix)
    for (let col = 1; col < n; col++) {
        const matrix = getMatrix(0, col);
        matrix.sort((a, b) => a - b); // Ascending
        setMatrix(0, col, matrix);
    }

    return grid;
};