Risinājums C# & Rust http://endijs.com/2014/11/21/programmetaji-ka-butu-ar-nelielu-skriptu/

secret_santa.rs

use std::char;
use std::rand::{Rng, task_rng};

// identisks tam pašam, kas C#
fn main() {
  let mut people: Vec<String> = range(0, 15).map(|i| char::from_u32(('A' as u32) + i).unwrap().to_string()).collect();
  let blacklist: Vec<Vec<&str>> = "A/B B/C D/E".split(' ').map(|pair| pair.split('/').collect()).collect();

  task_rng().shuffle(people.as_mut_slice());

  while people.len() > 0 {
    let giver = people.pop().unwrap();
    let receiver = people.iter().position(|candidate|
      !blacklist.iter().any(|ref pair| *pair[0] == **candidate && *pair[1] == *giver) &&
      !blacklist.iter().any(|ref pair| *pair[1] == **candidate && *pair[0] == *giver));

    match receiver {
      Some(index) => {
        println!("{} dāvina dāvanu {}", giver, people.index(&index));
        people.remove(index);
      },
      None => {
        println!("{} nav pārīša", giver);
      }
    }
  }
}

secret_santa2.rs

use std::io;
use std::collections::HashSet;
use std::rand::{Rng, task_rng};

// tas pats primitīvais algoritms, kas iepriekš, bet ātrs
// kā arī cilvēki un pārīši (un ģimenes) tiek ņemtas no vieniem ievaddatiem
fn main() {
  // ievaddati:
  // A       (viens cilvēks)
  // B C     (pārītis)
  // D E F   (ģimene - pārīši D E, D F un E F)
  let lines: Vec<String> = io::stdin().lines().map(|line| line.unwrap()).collect();

  let mut people = HashSet::new();
  let mut blacklist = HashSet::new();

  for line in lines.iter() {
    let group: Vec<&str> = line.trim().split(' ').collect();
    for i in range(0, group.len()) {
      people.insert(group[i]);
      for j in range(i + 1, group.len()) {
        people.insert(group[j]);
        blacklist.insert((group[i], group[j]));
      }
    }
  }

  let mut people: Vec<&str> = people.into_iter().collect();
  task_rng().shuffle(people.as_mut_slice());

  while !people.is_empty() {
    let giver = people.pop().unwrap();
    let receiver = people.iter().position(|&candidate|
      !blacklist.contains(&(giver, candidate)) &&
      !blacklist.contains(&(candidate, giver)));

    match receiver {
      Some(index) => {
        println!("{} dāvina dāvanu {}", giver, people.index(&index));
        people.swap_remove(index);
      },
      None => {
        println!("{} nav pārīša", giver);
      }
    }
  }
}

// vienu miljonu cilvēku izlozē vienā sekundē:
// seq 1 1000000 > 1m.txt
// time secret_santa2 < 1m.txt > /dev/null
// real    0m0.991s

SecretSanta.cs

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

// algoritms tik elementārs, cik vien iespējams, kā arī neefektīvs
// netiek ņemti vērā speciāl/robežgadījumi
class SecretSanta
{
    static void Main()
    {
        // string[] people = File.ReadLines("people.txt");
        // string[][] blacklist = File.ReadLines("blacklist.txt").Select(line => line.Split('\t')).ToArray();

        string[] people = Enumerable.Range(0, 15).Select(i => ((char)('A' + i)).ToString()).ToArray();
        string[][] blacklist = "A/B B/C D/E".Split(' ').Select(pair => pair.Split('/')).ToArray();

        Random random = new Random();
        List<string> list = people.Distinct().OrderBy(person => random.Next()).ToList();

        while (list.Count > 0)
        {
            string giver = list.First();
            string receiver = (from candidate in list
                               where candidate != giver
                               where !blacklist.Any(pair => pair[0] == candidate && pair[1] == giver)
                               where !blacklist.Any(pair => pair[1] == candidate && pair[0] == giver)
                               select candidate).FirstOrDefault();
            
            if (receiver != null)
                Console.WriteLine("{0} dāvina dāvanu {1}", giver, receiver);
            else
                Console.WriteLine("{0} nav pārīša", giver);

            list.Remove(giver);
            list.Remove(receiver);
        }
    }
}