diff --git a/.gitignore b/.gitignore
index 446fe69..dd7eee6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
 # @help: https://git-scm.com/docs/gitignore
+
+target/
diff --git a/s3_dsa/p01/.gitignore b/s3_dsa/p01/.gitignore
new file mode 100644
index 0000000..e40c306
--- /dev/null
+++ b/s3_dsa/p01/.gitignore
@@ -0,0 +1,3 @@
+# @help: https://git-scm.com/docs/gitignore
+
+*.bin
diff --git a/s3_dsa/p01/Cargo.lock b/s3_dsa/p01/Cargo.lock
new file mode 100644
index 0000000..54f07f9
--- /dev/null
+++ b/s3_dsa/p01/Cargo.lock
@@ -0,0 +1,69 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "bytemuck"
+version = "1.19.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8334215b81e418a0a7bdb8ef0849474f40bb10c8b71f1c4ed315cff49f32494d"
+
+[[package]]
+name = "fern"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69ff9c9d5fb3e6da8ac2f77ab76fe7e8087d512ce095200f8f29ac5b656cf6dc"
+dependencies = [
+ "log",
+]
+
+[[package]]
+name = "gen"
+version = "0.1.0"
+dependencies = [
+ "nanorand",
+]
+
+[[package]]
+name = "humantime"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
+
+[[package]]
+name = "log"
+version = "0.4.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
+
+[[package]]
+name = "nacci"
+version = "0.1.0"
+dependencies = [
+ "log",
+]
+
+[[package]]
+name = "nanorand"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a51313c5820b0b02bd422f4b44776fbf47961755c74ce64afc73bfad10226c3"
+
+[[package]]
+name = "polyphase"
+version = "0.1.0"
+dependencies = [
+ "bytemuck",
+ "log",
+ "nacci",
+]
+
+[[package]]
+name = "sort"
+version = "0.1.0"
+dependencies = [
+ "fern",
+ "humantime",
+ "log",
+ "polyphase",
+]
diff --git a/s3_dsa/p01/Cargo.toml b/s3_dsa/p01/Cargo.toml
new file mode 100644
index 0000000..d627abf
--- /dev/null
+++ b/s3_dsa/p01/Cargo.toml
@@ -0,0 +1,23 @@
+#:schema https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/cargo.json
+# @help: https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[workspace]
+default-members = ["./src/bin/sort/"]
+members = [
+    "./src/bin/gen/",
+    "./src/bin/sort/",
+    "./src/lib/nacci/",
+    "./src/lib/polyphase/",
+]
+resolver = "2"
+
+[workspace.dependencies]
+log = "0.4.22"
+
+[workspace.package]
+authors = ["fruzitent <fruzit@gmail.com>"]
+description = "s3_dsa/p01"
+edition = "2021"
+license-file = "license.md"
+readme = "readme.md"
+repository = "git+https://github.com/fruzitent/kpi.git"
diff --git a/s3_dsa/p01/rust-toolchain.toml b/s3_dsa/p01/rust-toolchain.toml
new file mode 100644
index 0000000..15badae
--- /dev/null
+++ b/s3_dsa/p01/rust-toolchain.toml
@@ -0,0 +1,5 @@
+#:schema https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/rust-toolchain.json
+# @help: https://rust-lang.github.io/rustup/overrides.html#the-toolchain-file
+
+[toolchain]
+channel = "stable"
diff --git a/s3_dsa/p01/rustfmt.toml b/s3_dsa/p01/rustfmt.toml
new file mode 100644
index 0000000..0192a88
--- /dev/null
+++ b/s3_dsa/p01/rustfmt.toml
@@ -0,0 +1,4 @@
+#:schema https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/rustfmt.json
+# @help: https://rust-lang.github.io/rustfmt
+
+max_width = 120
diff --git a/s3_dsa/p01/src/bin/gen/Cargo.toml b/s3_dsa/p01/src/bin/gen/Cargo.toml
new file mode 100644
index 0000000..2567458
--- /dev/null
+++ b/s3_dsa/p01/src/bin/gen/Cargo.toml
@@ -0,0 +1,21 @@
+#:schema https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/cargo.json
+# @help: https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[build-dependencies]
+
+[dependencies]
+nanorand = "0.7.0"
+
+[dev-dependencies]
+
+[features]
+
+[package]
+authors.workspace = true
+description.workspace = true
+edition.workspace = true
+license-file.workspace = true
+name = "gen"
+readme.workspace = true
+repository.workspace = true
+version = "0.1.0"
diff --git a/s3_dsa/p01/src/bin/gen/src/main.rs b/s3_dsa/p01/src/bin/gen/src/main.rs
new file mode 100644
index 0000000..deafbac
--- /dev/null
+++ b/s3_dsa/p01/src/bin/gen/src/main.rs
@@ -0,0 +1,11 @@
+fn main() {
+    let path = std::path::Path::new("./input.bin");
+    let size = usize::pow(2, 30);
+
+    let mut data = vec![0; size];
+    let mut rng = nanorand::tls_rng();
+    nanorand::Rng::fill_bytes(&mut rng, &mut data);
+
+    let mut file = std::fs::File::create(path).unwrap();
+    std::io::Write::write_all(&mut file, &data).unwrap();
+}
diff --git a/s3_dsa/p01/src/bin/sort/Cargo.toml b/s3_dsa/p01/src/bin/sort/Cargo.toml
new file mode 100644
index 0000000..58dc07b
--- /dev/null
+++ b/s3_dsa/p01/src/bin/sort/Cargo.toml
@@ -0,0 +1,24 @@
+#:schema https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/cargo.json
+# @help: https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[build-dependencies]
+
+[dependencies]
+fern = "0.7.0"
+humantime = "2.1.0"
+log.workspace = true
+polyphase = { path = "../../lib/polyphase/" }
+
+[dev-dependencies]
+
+[features]
+
+[package]
+authors.workspace = true
+description.workspace = true
+edition.workspace = true
+license-file.workspace = true
+name = "sort"
+readme.workspace = true
+repository.workspace = true
+version = "0.1.0"
diff --git a/s3_dsa/p01/src/bin/sort/src/main.rs b/s3_dsa/p01/src/bin/sort/src/main.rs
new file mode 100644
index 0000000..0801382
--- /dev/null
+++ b/s3_dsa/p01/src/bin/sort/src/main.rs
@@ -0,0 +1,24 @@
+fn setup_logger() -> Result<(), fern::InitError> {
+    fern::Dispatch::new()
+        .format(|out, message, record| {
+            out.finish(format_args!(
+                "[{} {} {}:{}] {}",
+                humantime::format_rfc3339_seconds(std::time::SystemTime::now()),
+                record.level(),
+                record.file().unwrap(),
+                record.line().unwrap(),
+                message
+            ))
+        })
+        .level(log::LevelFilter::Debug)
+        .chain(std::io::stdout())
+        .apply()?;
+    Ok(())
+}
+
+fn main() {
+    setup_logger().unwrap();
+    let input_path = std::path::Path::new("./input.bin");
+    let output_path = std::path::Path::new("./output.bin");
+    polyphase::sort(input_path, output_path, false, 3);
+}
diff --git a/s3_dsa/p01/src/lib/nacci/Cargo.toml b/s3_dsa/p01/src/lib/nacci/Cargo.toml
new file mode 100644
index 0000000..d8f0d95
--- /dev/null
+++ b/s3_dsa/p01/src/lib/nacci/Cargo.toml
@@ -0,0 +1,21 @@
+#:schema https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/cargo.json
+# @help: https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[build-dependencies]
+
+[dependencies]
+log.workspace = true
+
+[dev-dependencies]
+
+[features]
+
+[package]
+authors.workspace = true
+description.workspace = true
+edition.workspace = true
+license-file.workspace = true
+name = "nacci"
+readme.workspace = true
+repository.workspace = true
+version = "0.1.0"
diff --git a/s3_dsa/p01/src/lib/nacci/src/lib.rs b/s3_dsa/p01/src/lib/nacci/src/lib.rs
new file mode 100644
index 0000000..3957279
--- /dev/null
+++ b/s3_dsa/p01/src/lib/nacci/src/lib.rs
@@ -0,0 +1,80 @@
+/// @see: https://en.wikipedia.org/wiki/Generalizations_of_Fibonacci_numbers#Fibonacci_numbers_of_higher_order
+pub struct Nacci {
+    // TODO: replace usize with T
+    cache: Vec<usize>,
+    index: usize,
+    total: usize,
+}
+
+impl Nacci {
+    pub fn new(order: usize) -> Option<Self> {
+        if order < 2 {
+            // TODO: https://en.wikipedia.org/wiki/Negafibonacci_coding
+            return None;
+        }
+        let mut cache = vec![0; order];
+        cache[order - 1] = 1;
+        Some(Self {
+            cache,
+            index: 0,
+            total: 1,
+        })
+    }
+}
+
+impl Iterator for Nacci {
+    type Item = usize;
+
+    fn collect<B>(self) -> B
+    where
+        B: FromIterator<Self::Item>,
+        Self: Sized,
+    {
+        FromIterator::from_iter(self)
+    }
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let result = self.cache[self.index];
+        self.cache[self.index] = self.total;
+        self.index = (self.index + 1) % self.cache.len();
+        self.total = self.total * 2 - result;
+        Some(result)
+    }
+}
+
+pub fn get_dist(length: usize, tape_count: usize) -> Vec<usize> {
+    let fib = Nacci::new(tape_count - 1).unwrap();
+    let mut levels: Vec<usize> = vec![0; tape_count - 1];
+    for (i, val) in fib.enumerate() {
+        levels[i % (tape_count - 1)] = val;
+        let total: usize = levels.iter().sum();
+        log::debug!("i={i:?}, val={val:?}, levels={levels:?}, total={total:?}", i = i + 1);
+        if total >= length {
+            break;
+        }
+    }
+    levels
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        assert!(Nacci::new(1).is_none());
+        assert_eq!(
+            Nacci::new(2).unwrap().take(16).collect::<Vec<_>>(),
+            vec![0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
+        );
+        assert_eq!(
+            Nacci::new(3).unwrap().take(16).collect::<Vec<_>>(),
+            vec![0, 0, 1, 1, 2, 4, 7, 13, 24, 44, 81, 149, 274, 504, 927, 1705]
+        );
+        assert_eq!(
+            Nacci::new(4).unwrap().take(16).collect::<Vec<_>>(),
+            vec![0, 0, 0, 1, 1, 2, 4, 8, 15, 29, 56, 108, 208, 401, 773, 1490]
+        );
+        assert_eq!(Nacci::new(5).unwrap().take(0).collect::<Vec<usize>>(), vec![]);
+    }
+}
diff --git a/s3_dsa/p01/src/lib/polyphase/Cargo.toml b/s3_dsa/p01/src/lib/polyphase/Cargo.toml
new file mode 100644
index 0000000..cc0becb
--- /dev/null
+++ b/s3_dsa/p01/src/lib/polyphase/Cargo.toml
@@ -0,0 +1,24 @@
+#:schema https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/cargo.json
+# @help: https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[build-dependencies]
+
+[dependencies]
+bytemuck = "1.19.0"
+log.workspace = true
+nacci = { path = "../nacci/" }
+
+[dev-dependencies]
+
+[features]
+init_merge = []
+
+[package]
+authors.workspace = true
+description.workspace = true
+edition.workspace = true
+license-file.workspace = true
+name = "polyphase"
+readme.workspace = true
+repository.workspace = true
+version = "0.1.0"
diff --git a/s3_dsa/p01/src/lib/polyphase/src/lib.rs b/s3_dsa/p01/src/lib/polyphase/src/lib.rs
new file mode 100644
index 0000000..f417ef2
--- /dev/null
+++ b/s3_dsa/p01/src/lib/polyphase/src/lib.rs
@@ -0,0 +1,139 @@
+const CHUNK_SIZE: usize = 4096;
+
+fn comparator<T>(a: T, b: T, reverse: bool) -> bool
+where
+    T: Ord,
+{
+    if reverse {
+        a > b
+    } else {
+        a < b
+    }
+}
+
+fn process_file<F>(file: std::fs::File, chunk_size: usize, mut callback: F)
+where
+    F: FnMut(&[u8]),
+{
+    let mut reader = std::io::BufReader::with_capacity(chunk_size, file);
+    loop {
+        let mut buffer = vec![0; chunk_size].into_boxed_slice();
+        let length = std::io::Read::read(&mut reader, &mut buffer).unwrap();
+        if length == 0 {
+            break;
+        }
+        callback(&buffer[..length]);
+    }
+}
+
+fn process_chunk(runs: &mut Vec<Vec<i32>>, data: &[i32], reverse: bool) {
+    #[cfg(feature = "init_merge")]
+    let mut run = runs.last_mut().unwrap();
+
+    for &curr in data.iter() {
+        #[cfg(not(feature = "init_merge"))]
+        // TODO: unused variable: reverse
+        runs.push(vec![curr]);
+
+        #[cfg(feature = "init_merge")]
+        match run.last() {
+            Some(&prev) => {
+                if comparator(prev, curr, reverse) {
+                    run.push(curr);
+                } else {
+                    runs.push(vec![curr]);
+                    run = runs.last_mut().unwrap();
+                }
+            }
+            None => {
+                run.push(curr);
+            }
+        }
+    }
+}
+
+type Tape<T> = Vec<Vec<T>>;
+
+fn write_to_tape<T>(series: Tape<T>, dist: &mut [usize], tapes: &mut [Tape<T>])
+where
+    T: Clone,
+{
+    let mut iter = series.iter();
+    for (i, fib) in dist.iter_mut().enumerate() {
+        while *fib != 0 {
+            if let Some(s) = iter.next() {
+                tapes[i].push(s.clone());
+            } else {
+                tapes[i].push(vec![]);
+            }
+            *fib -= 1;
+        }
+    }
+}
+
+/// @see: https://en.wikipedia.org/wiki/Polyphase_merge_sort
+pub fn sort(input_path: &std::path::Path, output_path: &std::path::Path, reverse: bool, tape_count: usize) {
+    if tape_count >= 8 {
+        log::warn!("balanced_merge_sort() may perform better at 8 or more tapes");
+    }
+
+    let mut series: Tape<i32> = vec![
+        #[cfg(feature = "init_merge")]
+        vec![],
+    ];
+
+    let input_file = std::fs::File::open(input_path).unwrap();
+    process_file(input_file, CHUNK_SIZE, |buffer| {
+        let data: &[i32] = bytemuck::try_cast_slice(buffer).unwrap();
+        process_chunk(&mut series, data, reverse);
+    });
+    log::debug!("series={series:?}");
+
+    let mut dist = nacci::get_dist(series.len(), tape_count);
+    log::debug!("dist={dist:?}");
+
+    let mut tapes: Vec<Tape<i32>> = vec![vec![]; tape_count];
+    write_to_tape(series, &mut dist, &mut tapes);
+    log::debug!("tapes={tapes:?}");
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn add_dummy_series() {
+        let mut dist = vec![1, 2, 4];
+        let series: Tape<i32> = vec![vec![6], vec![3, 20], vec![15], vec![13], vec![8, 10, 17], vec![1]];
+        let tape_count: usize = 4;
+
+        let mut tapes: Vec<Tape<i32>> = vec![vec![]; tape_count];
+        write_to_tape(series, &mut dist, &mut tapes);
+        assert_eq!(
+            tapes,
+            vec![
+                vec![vec![6]],
+                vec![vec![3, 20], vec![15]],
+                vec![vec![13], vec![8, 10, 17], vec![1], vec![]],
+                vec![],
+            ]
+        );
+    }
+
+    #[test]
+    fn get_series() {
+        let mut series: Tape<i32> = vec![
+            #[cfg(feature = "init_merge")]
+            vec![],
+        ];
+
+        let data: &[i32] = &[5, 4, 3, 7, 6, 9];
+        process_chunk(&mut series, data, true);
+
+        #[cfg(feature = "init_merge")]
+        assert_eq!(series, vec![vec![5, 4, 3], vec![7, 6], vec![9]]);
+
+        #[cfg(not(feature = "init_merge"))]
+        assert_eq!(series, vec![vec![5], vec![4], vec![3], vec![7], vec![6], vec![9]]);
+    }
+}