19.py

day = 1
year = 1900
mons = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

fom_sundays = 0

def is_leap_year(year):
    return year % 4 == 0 and (year % 100 != 0 or year % 400 == 0)

while year < 2001:
    for mon in range(12):
        if day == 0 and year > 1900:
            fom_sundays += 1
        days = 29 if mon == 1 and is_leap_year(year) else mons[mon]
        day = (day + days) % 7
    year += 1

print fom_sundays

20.erl

#!/usr/bin/env escript

factorial(0) -> 1;
factorial(N) -> N * factorial(N - 1).

sum(List) -> sum(List, 0).

sum([], Total) -> Total;
sum([N | Rest], Total) -> sum(Rest, Total + N).

main(_) ->
    Fac = factorial(100),
    Result = sum([N - $0 || N <- integer_to_list(Fac)]),
    io:format("result is ~w~n", [Result]).

22.py

with open('22.txt') as f:
    names = f.read().strip().split(',')

base_value = ord('A') - 1
def word_score(word):
    return reduce(lambda tot, c: tot + ord(c) - base_value, word, 0)

total = sum([(k + 1) * word_score(v) for k, v in enumerate(sorted(names))])
print total