遍历C#列表，查找多个匹配字符串，并返回索引位置

using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    public static void Main(string[] args)
    {
        List<string> strings = new List<string>
        {
            "Hello",
            "World",
            "Foo",
            "Bar",
            "Baz"
        };

        List<string> searchStrings = new List<string>
        {
            "World",
            "Foo",
            "Qux"
        };

        List<int> indexes = searchStrings
            .SelectMany(searchString => strings.Select((value, index) => new { value, index }))
            .Where(x => x.value.Contains(searchStrings))
            .Select(x => x.index)
            .ToList();

        foreach (int index in indexes)
        {
            Console.WriteLine(index);
        }
    }
}