diff --git a/day06/common.rs b/day06/common.rs
new file mode 100644
index 0000000..eebe497
--- /dev/null
+++ b/day06/common.rs
@@ -0,0 +1,44 @@
+// Copyright 2022 Christian Ulrich
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::io::{self, Read};
+
+pub struct DatastreamWindows<const N: usize> {
+    window: [u8; N],
+}
+
+impl<const N: usize> DatastreamWindows<N> {
+    pub fn from_stdin() -> Result<Self, &'static str> {
+        let mut window = [0; N];
+        io::stdin()
+            .read_exact(&mut window[1..N])
+            .map_err(|_| "not enough data available")?;
+        Ok(Self { window: window })
+    }
+}
+
+impl<const N: usize> Iterator for DatastreamWindows<N> {
+    type Item = [u8; N];
+
+    fn next(&mut self) -> Option<Self::Item> {
+        for byte in io::stdin().bytes() {
+            let byte = byte.unwrap();
+            self.window.rotate_left(1);
+            self.window[N - 1] = byte;
+            return Some(self.window);
+        }
+        None
+    }
+}
diff --git a/day06/input b/day06/input
new file mode 100644
index 0000000..e683a34
--- /dev/null
+++ b/day06/input
@@ -0,0 +1,2 @@
+sgrrrrwcrrlqqgppfgfnngsgcgngrrllnqnndzzjgzzzjdjqdjdhhjshjhwwqnnwjnwnjwjttvgvddjrrtvtsvtvqtqhhbchcdhhnwwvqvvsbsqswqqdwdjwwjvvrddgpdpdlpljjwffqnffbllplmmwzwtzzvfzvvjbbmnmppzgzszllsqqpvqvmmzzlccjhchdhlddchdchcddnwdwhhhczzldlsdlssdmmswswzwtwzwjzwzfwwdhwdwjdjldjldlqddhttfbfnbfnfgnfnvnffsszjjsqqdzdsdrsswddggstgsgqgzqgqcqdccqcvcpcspccdgccfflppddqfdfmdffmlflplnppfvvgsgbgtgccmfccfwwthhcjcbbhbwbjbhjjtddrldlrddzjdzdttbfbmmtjmjtjzjvjvgvttthwhhgqhggcbbtqbbqgbqqvccdttfgfwfnwffbfqbfbbnlnzlzbbwnwntwtjwjnjwwsdwwcbbwhwzwhwvhhpwwnvvtvnttgtrrnjjzppmbmfmjffdddvfvjjpfpgpzzwqwpwllwjjzmjmdmdwwdrdttpmmdhdndvvpbpqbbzqzmmtdmmtddlccjvjsjrsscqqzvvbsstccvffcttwrwjjsgsttmgmvvzbbcjbjrbrddvjjnhjhphvhsszqqfrfzfssgfssgddcbbplbbsfsmfmpphssmvvcvrrcgrcgcvggrzggzjjfhjjtpphzppqtptllssbmbrrgrvvhjjnznlnggrnrsnrrphhbqhhhsthsthhhnssmsjjwjppqfqlqqgnnhnmmfsfslfllvnnsdnssgngbbjmjccsrrmjjnljlwlttpffddgbdggmbgbtbzzwgwppczcffvccnssbmmjrrfwwhcwhwqwnqqzsqqjsqqnndqdgqdqgggzjjcvvzdddhnhjnnzlnlwlzlqqvjjpprqrjrfjjrpjjnfntffqtttnjjdbjbdjbbrsrbbmrmccpllmccqrqwqnnsjjmjgjqjpqjqgjjtwwqdqmqtqqmsqmmvlldtllbcctfcccdcddcggmmmsggjddcqddbqqdgqgffststgtftbbdrbrlllnvllcflfpfdffjvvvmdmvvtfvfcvvfgghzzlgzgszzhmzzhfhllgblggfpfzfvzvdzzhsspmmjtjhjggfhggnggbtggqqtztqtmqtqddmzmrmdrmdmqqcbqcqzzvczvzfvvsggcgssjnnjqnntwtmwwhzzzhllqvlljsljjfnnjwjnwnffpggqwwvbwwdbbmbvmvlvnnnppqvqqghqgqppnllhjllvlflfpfhfjjhgjgpjpbjjdpdqdpqdpdwpwffqlffrbrjrtrvtvrtvrtrvtvltlrrvjjlttmtffhvfhfnhnlnfnvvltvlvlbbfllfnllndndcdrrnznssvpvhhhmrmlmhhrnhhpggtftddghhqrqddjttbdbqddpsdppwrwhhhgwhhqrhqrqhhqdhqddjpjqqsdsmddnqncqnqwqdwwhghbhffnsffnsszlssntnbbbfhbhwhzhdzhzbhblbzzzbqzbbgtbbcjbjtjptpwwhlwwhhmshhmbbfjbfflnnlmnnzvnnbtnbbvwvvgcggrzrffwmwhmwhwjwpwwzbbvtbtssdhdlhhdppmmcnmcmffnpfffvbfvfhvhjhffzfbzzfdfpdpzzhbzblbbmffvvcmmttdntnmtmztzbbncbctcqtcqqcvcfcwcdcchphfhjhhjbjnjtjnjwwzsstpprnnhtntvtpthpttpdpzzwcczsscqscsbbmpbbdsdlsslzszjszsczntrqjmmmfqsdwtqqflgsttwfqqvvspnlfvqlrvvbjmmpmttcdnhncmmdfhwwqdrqjqwggrbtgbrdmmrhhvqfvvhsmtfbnthrbltgvdrsbqglgjqtssbvmbjjjbbcgfftgbjmfqzggdtcfzddqlrvwqjjvnmjzjwqrwsqbjgnswpnlbdzdlcvcbqplzgqwmsntzzjhqwfjdprglcccnldfqftgttqbrmclsqtncrjbttcglcvspsgvdjqgrdzzlnhbfqbwnfqcjrrqpprjbqpzhthgsgcflqldsnwsvzgcmfrdvfmqhbcfczhschpwnmdjnjlvrwqllnnhjvjtzhcrqcwlmrqfdhvzcbnvwrgngttwlhcmmgtzwjztscjnmslbvtdrvgdprlfrhggcwtwjhblppfbpljbmwrlwqrfwjwfsftmflsdfrhlvgcbzcvhlhgclvnmtfcqttvcphgvflhdclbmtgsrldgfvtpjcphtzdctrcchwdbdbtpptdnbjnqwdrllmnbcgfltmggpqfbfpmnhcmpgsgptflglzswtmrjfzmwmwphfjngnfmmtqlrsltlvlfmwmjvvtgngllszwzdjjmbnwwgzpqltlrzfdwchgttvlhgjjhjqmlrrwsqlhsgzsgmmsgbgvrlmbprrhlgsjnsdwcbrwvqjqmfcqcwllsvggcznwpzvgpszrqwngcnchvdlrdrgtbsjdqfpsfvwdtdlqwbfjlwrmqbrhwqmfgppwvfbgthnbqnmqqhmpfwbgljcmqqbpnwvztrcrlbvtcnncwwjcbqsmbqnqtrmpwmhlvwtfmsmtpfnmphqdvqfzvmjjhnwdfjnwvmbbwvthhwzjtzzrsmqlqtnnrqjrnchqttgsptfpdcpgfmzvqhwffqmfhwqqbdhmgcrfqtwrcgtgmglmmwhvqwvglfsvwbpvhmnbqhgfgqwwnhdhvnwggsmhjfsjmsrlcvlnhrhrlhbvhdrhbplrzspdmbcnzbwlvcmztwvghlsnzmbnrpssrngpdtmgzfcbqmfdgthcscjspspmcgdmwwwfspgjwzccrfzdpbwrfpgpgzrchffmhvwwppbjwqmdzgtpfmcblzqrghzdbzqzvbnmqbdlzjrwbbhqgtdzntgdbndmndhlnhcvqtlfcrfprfrlfglwvdnszrwjdcmtstcsnvnpcldctvqpcfhjnpvscscrtfqfjcrjlrmcqjfthptbqprbvchjlqzmfcmlhmfmdhhpcqbncmcqjsdmzflwtzfdcgmrbwbcdgjmfhlshsbwmbdcbfbvmqcgwlqpprjfrhzvsjmcjdfnwhcffhtnqpznfzpttsqqwcsvpdhdfbggzpngvbvdlpmvfjjlcfmbvmfqsczprtlnwvqnnlcrdnvpmcbrzvlfgscbcwtrbcpdnpshhmrqmhnwcndptljhwpvtcflqgmzjsfmfdzwwwhnbpzjwzgqmdcdbtfhwtgvcscbdqlcmppwjgghvrmqpwfbnjfhfcrccfzjvtjsjcsmhncdjlclvhfsvlcjcnpbqqqdjmjdbggmfwswvdjscvgrdbpcrcqtndswgdnznzpwtcdgvcrrqpdcpbmbdjrsgnfvgwpgpzttfmsczcmjvhmdpbpmjjcjsvbvbwjpwtwpsdddlsnvrshqvmwsjwwvqnczzljjfptcszgpndgczprbvjbnqpwgzmnlhvbsfbtjnwbtlzqgnmzbmqgqvwzltvqczfpdzfzsfhqlmtfcbfdqtnwzbvqblqmzvmnspntqtqdglrdmdntrghwvpfrbjgpzvrnppvnvfgwdzlvhtcscclbtftlvsprwhjvjlhrhfdgzbfbfphzbhtfdlpzcshhfzhtdvggnnbqvnrwvnhvgjgjpcrztqjmtzlzlrlmndfvctzjdpnmlgmsppqdrzmptvrsptvmmbvbwvhwptrtlfdqdqwfgldtbhqdhszcmwqnhswrdhgmgvbvbhwhlpcflsrwlvsvhvctmwwhtlgmshdqflwsdjbbzgbvbwpfncgqjzfjvmzzhgdzjvghtrtsmwgzpdrngwdbtfzrqsgdmwtdhsftfqcnmjtrqqwthcbgtmqnjvjzzplrzllnjqddvbwnglhtzljwjvscdfdnsvmrgwhjrhlrqpqgmzstnwwjpddhdbsnnsqvtsdhtmfdmbcpzwqmbhhjhcfzbvvglhfdltrmbstjhsqrbs
+
diff --git a/day06/part1.rs b/day06/part1.rs
new file mode 100644
index 0000000..7f369e8
--- /dev/null
+++ b/day06/part1.rs
@@ -0,0 +1,36 @@
+// Copyright 2022 Christian Ulrich
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// usage: ./part1 < input
+
+pub mod common;
+
+use common::DatastreamWindows;
+
+fn main() -> Result<(), &'static str> {
+    const WINDOW_SIZE: usize = 4;
+    let mut result = WINDOW_SIZE;
+    for window in DatastreamWindows::<WINDOW_SIZE>::from_stdin()? {
+        if window
+            .iter()
+            .all(|byte| window.iter().filter(|b| b == &byte).count() == 1)
+        {
+            break;
+        }
+        result += 1;
+    }
+    println!("{result}");
+    Ok(())
+}
diff --git a/day06/testinput b/day06/testinput
new file mode 100644
index 0000000..7980a82
--- /dev/null
+++ b/day06/testinput
@@ -0,0 +1 @@
+mjqjpqmgbljsphdztnvjfqwrcgsmlb