open System

let file_read = System.IO.File.ReadAllText @"D:\input.txt"
let file_write = new System.IO.FileInfo @"D:\output.txt"

let search_names (sent : String) (names : Map<String, Set<int>>) index : Map<String, Set<int>> =
    let words = sent.Split([|' '; ','; ';'; '"';'\r'; '\n'; '\t'; ':'; '-'|])
    let rec search_names_rec (names_rec : Map<String, Set<int>>) i =
        match i with
        | a when a = words.Length -> names_rec
        | _ -> words.[i].Trim([|'.'; '!'; '?'; ' '; ')'; '('; ','; ';'; '"'; '\'' ;'\r'; '\n'; '\t'|])  |> (fun word ->
            if word.Length > 1 && Char.IsUpper(word.[0]) && not (Char.IsUpper(word.[1]))
            then
                let w =
                    if word.[word.Length - 2] = '\'' && word.[word.Length - 1] = 's'
                    then word.Remove(word.Length - 2)
                    else word
                if names_rec.ContainsKey(w)
                then search_names_rec (names_rec.Add(w, names_rec.[w].Add(index))) (i + 1)
                else search_names_rec (names_rec.Add(w, Set.empty.Add(index))) (i + 1)
            else search_names_rec names_rec (i + 1))
    search_names_rec names 1

type pair = string * string * int

let exclusion = ["Russia"; "Russian"; "French"; "Princess"; "Prince"; "Emperor"; "Moscow"; "Count"; "Smolensk"; "Petersburg"; "Mademoiselle"; "His"; "Her"; "Project"; "Hills"; "Guards"; "The"; "Uncle"; "Countess"; "Tsar"; "German"; "Austrian"; "General"; "God"; "Charmee"; "Go"; "Get"; "From"; "However"; "When"; "Where"; "How"; "What"; "King"; "Kiss"; "King"; "A"; "Your"; "We"; "About"; "After"; "Street"; "Ah"; "An";"War";"And";"You";"That";"They";"These";"This";"She"]

let main (text : String) : pair list =
    let sentences = text.Split([|'.'; '!'; '?'|]);

    let rec global_search (names : Map<string, Set<int>>) i : Map<string, Set<int>> =
        if (i < sentences.Length)
        then global_search (search_names (sentences.[i].Trim([|'.'; '!'; '?'; ' '; '’'; '\''|])) names i) (i + 1)
        else names

    let map = Map.filter (fun word _ -> not (List.exists (fun elem -> elem = word) exclusion)) (global_search Map.empty 0)

    let pairs = [ for n1 in map do
                      for n2 in map do
                      let c = Set.count(Set.intersect n1.Value n2.Value)
                      if (n1.Key < n2.Key) && (c > 0) then yield (n1.Key, n2.Key, c)]

    let sort (p1 : pair) (p2 : pair) =
        let n (_, _, c) = c
        if (n p1 > n p2)
        then -1
        else 1
    List.sortWith sort pairs

if not file_write.Exists then
    using (file_write.CreateText()) (fun stream ->
                                for str in (main file_read) do
                                    stream.WriteLine(str.ToString()))