使用LINQ从子列表中选择最大值

List<List<int>> parentList = new List<List<int>>()
{
    new List<int>() { 1, 2, 3 },
    new List<int>() { 4, 5, 6 },
    new List<int>() { 7, 8, 9 }
};

var selectedLists = parentList.Select(list => list);

var maxValues = selectedLists.Select(list => list.Max());

int maxValue = parentList.SelectMany(list => list).Max();