static string FormatMatrix(int[][] matrix)
{
    var rows = new string[matrix.Length];
    for (var i = 0; i < matrix.Length; i++)
        rows[i] = "[" + string.Join(",", matrix[i]) + "]";
    return "[" + string.Join(",", rows) + "]";
}

var sol = new Solution();

var cases = new (int[][] input, string expected)[]
{
    (
        new[]
        {
            new[] { 1, 2 },
            new[] { 3, 4 }
        },
        "[[24,12],[8,6]]"
    ),
    (
        new[]
        {
            new[] { 12345 },
            new[] { 2 },
            new[] { 1 }
        },
        "[[2],[0],[0]]"
    ),
    (
        new[]
        {
            new[] { 4, 8, 8 },
            new[] { 6, 2, 5 },
            new[] { 7, 3, 7 },
            new[] { 6, 3, 5 }
        },
        "[[3525,7935,7935],[6465,7050,2820],[7305,585,7305],[6465,585,2820]]"
    ),
    (
        new[]
        {
            new[] { 4, 3, 9 },
            new[] { 3, 9, 10 },
            new[] { 9, 7, 8 },
            new[] { 8, 4, 7 },
            new[] { 6, 1, 3 }
        },
        "[[3255,225,75],[225,75,11178],[75,1860,7800],[7800,3255,1860],[6285,675,225]]"
    ),
    (
        new[]
        {
            new []{1,2,2},
            new []{1,4,3}
        },
        "[[48,24,24],[48,12,16]]"
    ),
    (
        new[]
        {
            new[] { 414750857 },
            new[] { 449145368 },
            new[] { 767292749 }
        },
        "[[1462],[3103],[9436]]"
    )
};

foreach (var (input, expected) in cases)
{
    var actual = sol.ConstructProductMatrix(input);
    Console.WriteLine($"{FormatMatrix(input)} -> {FormatMatrix(actual)} (expected: {expected})");
}