function largestRectAtRow(rowNum) {

		var area = [];
		var leftAdjCols = [];
		var rigthAdjCols = [];
		var i, t;
		var stack = [];

		for (i = 0; i < matrix.length; ++i) {

			while (stack.length != 0) {

				if (matrix[i][rowNum] <= matrix[stack[stack.length - 1]][rowNum]) {
					stack.pop();
				} else {
					break;
				}
			}
			if (stack.length == 0) {
				t = -1;
			} else {
				t = stack[stack.length - 1];
			}

			//  (i - t - 1): number of adjacent columns to the left of i-th column
			var leftAdj = (i - t - 1);
			leftAdjCols[i] = leftAdj;

			var leftSum = 0;
			for (var c = i - leftAdj; c < leftAdj; ++c) {
				leftSum += columnsWidths[c];
			}
			area[i] = leftSum;

			stack.push(i);
		}

		while (stack.length != 0) {
			stack.pop();
		}

		for (i = matrix.length - 1; i >= 0; --i) {

			while (stack.length != 0) {

				if (matrix[i][rowNum] <= matrix[stack[stack.length - 1]][rowNum]) {
					stack.pop();
				} else {
					break;
				}
			}
			if (stack.length == 0) {
				t = matrix.length;
			} else {
				t = stack[stack.length - 1];
			}

			//  (i - t - 1): number of adjacent columns to the right of i-th column
			var rigthAdj = t - i - 1;
			var rigthSum = 0;
			rigthAdjCols[i] = rigthAdj;
			for (c = i + 1; c <= i + rigthAdj; ++c) {
				rigthSum += columnsWidths[c];
			}
			area[i] += rigthSum;

			stack.push(i);
		}

		var maxRect = {left: 0, top: 0, width: 0, height: 0};
		for (i = 0; i < matrix.length; ++i) {

			var width = area[i] + columnsWidths[i];
			var height = matrix[i][rowNum];

			if (maxRect.width * maxRect.height < width * height) {

				var top = 0;
				for (c = 0; c <= rowNum; ++c) {
					top += rowHeights[c];
				}
				top -= matrix[i][rowNum];

				var left = 0;
				for (c = 0; c < i; ++c) {
					left += columnsWidths[c];
				}
				for (c = 0; c < leftAdjCols[i]; ++c) {
					left -= columnsWidths[i - 1 - c];
				}

				maxRect = { left: left, top: top, width: width, height: height };
			}
		}

		return maxRect;
	}