maximalRectangle.js

/**
 * @param {character[][]} matrix
 * @return {number}
 */
var maximalRectangle = function(matrix) {
    if (matrix.length === 0) return 0; // If the matrix is empty, return 0

    var m = matrix.length;
    var n = matrix[0].length;
    var left = new Array(n).fill(0); // Initialize left, right and height arrays
    var right = new Array(n).fill(n);
    var height = new Array(n).fill(0);

    var maxArea = 0;

    for (var i = 0; i < m; i++) {
        var cur_left = 0, cur_right = n;

        // Update height
        for (var j = 0; j < n; j++) {
            if (matrix[i][j] === '1') height[j]++;
            else height[j] = 0;
        }

        // Update left
        for (var j = 0; j < n; j++) {
            if (matrix[i][j] === '1') left[j] = Math.max(left[j], cur_left);
            else { left[j] = 0; cur_left = j + 1; }
        }

        // Update right
        for (var j = n - 1; j >= 0; j--) {
            if (matrix[i][j] === '1') right[j] = Math.min(right[j], cur_right);
            else { right[j] = n; cur_right = j; }
        }

        // Update the area
        for (var j = 0; j < n; j++)
            maxArea = Math.max(maxArea, (right[j] - left[j]) * height[j]);
    }

    return maxArea;
};