See the original problem on HackerRank.
Solutions
We can count the on time students. If the count is less than k, the professor is angry.
PHP
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<?php
function angryProfessor($k, $a) {
$count = 0;
foreach ($a as $time) {
if ($time <= 0) {
$count++;
}
}
if ($count >= $k) {
return 'NO';
}
else {
return 'YES';
}
}
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Javascript by Enrico Scantamburlo
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const angryProfessor = (k, a) => a.filter(v => v < 1).length < k ? 'YES' : 'NO'
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Ruby by Davide Pettenon
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def angryProfessor(k, a)
a.select { |x| x <= 0 }.size < k ? 'YES' : 'NO'
end
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Python by Beatrice Liberi
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def angryProfessor(k, a):
if len(list(filter(lambda x: x <=0, a))) >= k :
return 'NO'
else:
return 'YES'
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Haskell
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import Data.List.Split
fromLines lines = (k, a)
where
_:k:a = read <$> concatMap words lines
countOnTime = length . filter (<= 0)
angryProfessor (k, a) = countOnTime a < k
output True = "YES"
output False = "NO"
main = do
_ <- getLine
testCases <- fmap fromLines . chunksOf 2 . lines <$> getContents
putStr . unlines $ output . angryProfessor <$> testCases
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The algorithm can be optimized: just stop reading the array when at least k
students are on time.
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angryProfessor (k, a) = k /= (length . take k $ filter (<= 0) a)
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Rust
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fn angry_professor(k: usize, a: &[i32]) -> bool {
k != a.iter().filter(|&&x| x <= 0).take(k).count()
}
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Elixir by Tommaso Bertagnin
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defmodule Solution do
[[_n_of_cases] | cases ] =
Enum.map(IO.stream(:stdio, :line), fn line ->
line
|> String.trim
|> String.split(" ", trim: true)
|> Enum.map(&String.to_integer/1)
end)
cases
|> Enum.chunk_every(2)
|> Enum.each(fn [[_n_students, min_attendance], entry_times] ->
arrived_on_time =
entry_times
|> Enum.filter(fn t -> t <= 0 end)
|> Enum.count()
professor_says =
if arrived_on_time >= min_attendance do "NO" else "YES" end
IO.write(professor_says <> "\n")
end)
end
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C++
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string angryProfessor(int k, vector<int> times)
{
return count_if(begin(times), end(times), [](int i){return i<=0;}) >=k ? "NO" : "YES";
}
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C++ with ranges:
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string angryProfessor(int k, vector<int> times)
{
return count_if(times, [](int i){return i<=0;}) >=k ? "NO" : "YES";
}
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