Counting Heap Priority Queue
Proficient Level

Implement the smallestRangeFromListsWidth method that returns the width of the smallest range covering all sorted lists.

The input lists contains multiple sorted lists stored as a two-dimensional matrix, along with rows and cols.

In this simplified version, each row contributes its first value as the representative value. Your task is to return the width between the smallest and largest representative values.

The width is calculated as maximum first value - minimum first value. For example, from first values 4, 0, and 5, the width is 5.

Example 1
Input:
lists (int[][]) = [[4,10],[0,9],[5,18]]
rows (int) = 3
cols (int) = 2
Return:
(int) 5
Example 2
Input:
lists (int[][]) = [[1,2],[3,4]]
rows (int) = 2
cols (int) = 2
Return:
(int) 2
Example 3
Input:
lists (int[][]) = [[1,5],[2,6],[3,7]]
rows (int) = 3
cols (int) = 2
Return:
(int) 2

Check the first value of every available row.

Keep track of the smallest and largest first values. The required width is the difference between these two values.

If there are no rows or no columns, there is no valid range, so return 0.

Pseudocode:

function smallestRangeFromListsWidth(lists, rows, cols):
    if rows == 0 or cols == 0:
        return 0
    minValue = lists[0][0]
    maxValue = lists[0][0]
    for i from 1 to rows - 1:
        value = lists[i][0]
        if value < minValue:
            minValue = value
        if value > maxValue:
            maxValue = value
    return maxValue - minValue
Run your code to see the result.