diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9658366..0c8fcba 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -76,6 +76,78 @@ jobs:
           profile: minimal
           components: clippy
 
+      - name: cargo-clippy (convolution)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features convolution -- -D warnings
+
+      - name: cargo-clippy (dsu)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features dsu -- -D warnings
+
+      - name: cargo-clippy (fenwicktree)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features fenwicktree -- -D warnings
+
+      - name: cargo-clippy (lazysegtree)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features lazysegtree -- -D warnings
+
+      - name: cargo-clippy (math)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features math -- -D warnings
+
+      - name: cargo-clippy (maxflow)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features maxflow -- -D warnings
+
+      - name: cargo-clippy (mincostflow)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features mincostflow -- -D warnings
+
+      - name: cargo-clippy (modint)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features modint -- -D warnings
+
+      - name: cargo-clippy (scc)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features scc -- -D warnings
+
+      - name: cargo-clippy (segtree)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features segtree -- -D warnings
+
+      - name: cargo-clippy (string)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features string -- -D warnings
+
+      - name: cargo-clippy (twosat)
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --workspace --all-targets --no-default-features --features twosat -- -D warnings
+
       - name: cargo-clippy
         uses: actions-rs/cargo@v1
         with:
diff --git a/Cargo.toml b/Cargo.toml
index 5348943..351cc50 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,40 @@ keywords = ["competitive"]
 categories = ["algorithms", "data-structures"]
 publish = false
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[[example]]
+name = "practice2_d_maxflow"
+path = "examples/practice2_d_maxflow.rs"
+required-features = ["maxflow"]
+
+[[example]]
+name = "practice2_j_segment_tree"
+path = "examples/practice2_j_segment_tree.rs"
+required-features = ["segtree"]
+
+[[example]]
+name = "practice2_k_range_affine_range_sum"
+path = "examples/practice2_k_range_affine_range_sum.rs"
+required-features = ["lazysegtree", "modint"]
+
+[[example]]
+name = "practice2_l_lazy_segment_tree"
+path = "examples/practice2_l_lazy_segment_tree.rs"
+required-features = ["lazysegtree"]
+
+[features]
+default = ["convolution", "dsu", "fenwicktree", "lazysegtree", "math", "maxflow", "mincostflow", "modint", "scc", "segtree", "string", "twosat"]
+convolution = ["modint"]
+dsu = []
+fenwicktree = []
+lazysegtree = ["segtree"]
+math = []
+maxflow = []
+mincostflow = []
+modint = []
+scc = []
+segtree = []
+string = []
+twosat = []
 
 [dependencies]
 
diff --git a/src/convolution.rs b/src/convolution.rs
index 9576e3e..d084e3a 100644
--- a/src/convolution.rs
+++ b/src/convolution.rs
@@ -8,9 +8,9 @@ macro_rules! modulus {
                 const VALUE: u32 = $name as _;
                 const HINT_VALUE_IS_PRIME: bool = true;
 
-                fn butterfly_cache() -> &'static ::std::thread::LocalKey<::std::cell::RefCell<::std::option::Option<crate::modint::ButterflyCache<Self>>>> {
+                fn butterfly_cache() -> &'static ::std::thread::LocalKey<::std::cell::RefCell<::std::option::Option<self::modint::ButterflyCache<Self>>>> {
                     thread_local! {
-                        static BUTTERFLY_CACHE: ::std::cell::RefCell<::std::option::Option<crate::modint::ButterflyCache<$name>>> = ::std::default::Default::default();
+                        static BUTTERFLY_CACHE: ::std::cell::RefCell<::std::option::Option<self::modint::ButterflyCache<$name>>> = ::std::default::Default::default();
                     }
                     &BUTTERFLY_CACHE
                 }
@@ -19,9 +19,9 @@ macro_rules! modulus {
     };
 }
 
-use crate::{
+use super::{
     internal_bit, internal_math,
-    modint::{ButterflyCache, Modulus, RemEuclidU32, StaticModInt},
+    modint::{self, ButterflyCache, Modulus, RemEuclidU32, StaticModInt},
 };
 use std::{
     cmp,
@@ -232,10 +232,7 @@ fn prepare<M: Modulus>() -> ButterflyCache<M> {
 
 #[cfg(test)]
 mod tests {
-    use crate::{
-        modint::{Mod998244353, Modulus, StaticModInt},
-        RemEuclidU32,
-    };
+    use super::super::modint::{self, Mod998244353, Modulus, RemEuclidU32, StaticModInt};
     use rand::{rngs::ThreadRng, Rng as _};
     use std::{
         convert::{TryFrom, TryInto as _},
diff --git a/src/internal_math.rs b/src/internal_math.rs
index 515191c..ce1aaa8 100644
--- a/src/internal_math.rs
+++ b/src/internal_math.rs
@@ -239,7 +239,7 @@ pub(crate) fn primitive_root(m: i32) -> i32 {
 mod tests {
     #![allow(clippy::unreadable_literal)]
     #![allow(clippy::cognitive_complexity)]
-    use crate::internal_math::{inv_gcd, is_prime, pow_mod, primitive_root, safe_mod, Barrett};
+    use super::{inv_gcd, is_prime, pow_mod, primitive_root, safe_mod, Barrett};
     use std::collections::HashSet;
 
     #[test]
diff --git a/src/internal_queue.rs b/src/internal_queue.rs
index 5e51e9a..5266591 100644
--- a/src/internal_queue.rs
+++ b/src/internal_queue.rs
@@ -51,7 +51,7 @@ impl<T> SimpleQueue<T> {
 
 #[cfg(test)]
 mod test {
-    use crate::internal_queue::SimpleQueue;
+    use super::SimpleQueue;
 
     #[allow(clippy::cognitive_complexity)]
     #[test]
diff --git a/src/internal_scc.rs b/src/internal_scc.rs
index dbdbdc4..85a0a72 100644
--- a/src/internal_scc.rs
+++ b/src/internal_scc.rs
@@ -45,6 +45,7 @@ impl SccGraph {
         SccGraph { n, edges: vec![] }
     }
 
+    #[allow(dead_code)]
     pub fn num_vertices(&self) -> usize {
         self.n
     }
@@ -115,6 +116,7 @@ impl SccGraph {
         (env.group_num, env.ids)
     }
 
+    #[allow(dead_code)]
     pub fn scc(&self) -> Vec<Vec<usize>> {
         let ids = self.scc_ids();
         let group_num = ids.0;
diff --git a/src/lazysegtree.rs b/src/lazysegtree.rs
index 47020a8..959fabf 100644
--- a/src/lazysegtree.rs
+++ b/src/lazysegtree.rs
@@ -1,5 +1,5 @@
-use crate::internal_bit::ceil_pow2;
-use crate::Monoid;
+use super::internal_bit::ceil_pow2;
+use super::segtree::Monoid;
 
 pub trait MapMonoid {
     type M: Monoid;
@@ -314,7 +314,8 @@ where
 
 #[cfg(test)]
 mod tests {
-    use crate::{LazySegtree, MapMonoid, Max};
+    use super::super::segtree::Max;
+    use super::{LazySegtree, MapMonoid};
 
     struct MaxAdd;
     impl MapMonoid for MaxAdd {
diff --git a/src/lib.rs b/src/lib.rs
index 5452b25..d3ef82c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,37 +1,66 @@
+#[cfg(feature = "convolution")]
 pub mod convolution;
+#[cfg(feature = "dsu")]
 pub mod dsu;
+#[cfg(feature = "fenwicktree")]
 pub mod fenwicktree;
+#[cfg(feature = "lazysegtree")]
 pub mod lazysegtree;
+#[cfg(feature = "math")]
 pub mod math;
+#[cfg(feature = "maxflow")]
 pub mod maxflow;
+#[cfg(feature = "mincostflow")]
 pub mod mincostflow;
+#[cfg(feature = "modint")]
 pub mod modint;
+#[cfg(feature = "scc")]
 pub mod scc;
+#[cfg(feature = "segtree")]
 pub mod segtree;
+#[cfg(feature = "string")]
 pub mod string;
+#[cfg(feature = "twosat")]
 pub mod twosat;
 
+#[cfg(any(feature = "convolution", feature = "lazysegtree", feature = "segtree"))]
 pub(crate) mod internal_bit;
+#[cfg(any(feature = "math", feature = "modint"))]
 pub(crate) mod internal_math;
+#[cfg(feature = "maxflow")]
 pub(crate) mod internal_queue;
+#[cfg(any(feature = "scc", feature = "twosat"))]
 pub(crate) mod internal_scc;
+#[cfg(any(feature = "maxflow", feature = "mincostflow", feature = "segtree"))]
 pub(crate) mod internal_type_traits;
 
+#[cfg(feature = "convolution")]
 pub use convolution::{convolution, convolution_i64};
+#[cfg(feature = "dsu")]
 pub use dsu::Dsu;
+#[cfg(feature = "fenwicktree")]
 pub use fenwicktree::FenwickTree;
+#[cfg(feature = "lazysegtree")]
 pub use lazysegtree::{LazySegtree, MapMonoid};
+#[cfg(feature = "math")]
 pub use math::{crt, floor_sum, inv_mod, pow_mod};
+#[cfg(feature = "maxflow")]
 pub use maxflow::{Edge, MfGraph};
+#[cfg(feature = "mincostflow")]
 pub use mincostflow::MinCostFlowGraph;
+#[cfg(feature = "modint")]
 pub use modint::{
     Barrett, ButterflyCache, DefaultId, DynamicModInt, Id, Mod1000000007, Mod998244353, ModInt,
     ModInt1000000007, ModInt998244353, Modulus, RemEuclidU32, StaticModInt,
 };
+#[cfg(feature = "scc")]
 pub use scc::SccGraph;
+#[cfg(feature = "segtree")]
 pub use segtree::{Additive, Max, Min, Monoid, Multiplicative, Segtree};
+#[cfg(feature = "string")]
 pub use string::{
     lcp_array, lcp_array_arbitrary, suffix_array, suffix_array_arbitrary, suffix_array_manual,
     z_algorithm, z_algorithm_arbitrary,
 };
+#[cfg(feature = "twosat")]
 pub use twosat::TwoSat;
diff --git a/src/math.rs b/src/math.rs
index 61f15d5..f29a819 100644
--- a/src/math.rs
+++ b/src/math.rs
@@ -1,6 +1,6 @@
 //! Number-theoretic algorithms.
 
-use crate::internal_math;
+use super::internal_math;
 
 use std::mem::swap;
 
diff --git a/src/maxflow.rs b/src/maxflow.rs
index 93b337c..6f884c4 100644
--- a/src/maxflow.rs
+++ b/src/maxflow.rs
@@ -1,6 +1,6 @@
 #![allow(dead_code)]
-use crate::internal_queue::SimpleQueue;
-use crate::internal_type_traits::Integral;
+use super::internal_queue::SimpleQueue;
+use super::internal_type_traits::Integral;
 use std::cmp::min;
 use std::iter;
 
@@ -224,7 +224,7 @@ struct _Edge<Cap> {
 
 #[cfg(test)]
 mod test {
-    use crate::{Edge, MfGraph};
+    use super::{Edge, MfGraph};
 
     #[test]
     fn test_max_flow_wikipedia() {
diff --git a/src/mincostflow.rs b/src/mincostflow.rs
index 158a9e8..aafc45e 100644
--- a/src/mincostflow.rs
+++ b/src/mincostflow.rs
@@ -1,4 +1,4 @@
-use crate::internal_type_traits::Integral;
+use super::internal_type_traits::Integral;
 
 pub struct MinCostFlowEdge<T> {
     pub from: usize,
diff --git a/src/modint.rs b/src/modint.rs
index 8aa5220..c47dfef 100644
--- a/src/modint.rs
+++ b/src/modint.rs
@@ -48,7 +48,7 @@
 //! [`ModInt998244353`]: ./type.ModInt998244353.html
 //! [`ModInt`]: ./type.ModInt.html
 
-use crate::internal_math;
+use super::internal_math;
 use std::{
     cell::RefCell,
     convert::{Infallible, TryInto as _},
@@ -283,7 +283,9 @@ impl Modulus for Mod998244353 {
 
 /// Cache for butterfly operations.
 pub struct ButterflyCache<M> {
+    #[allow(dead_code)]
     pub(crate) sum_e: Vec<StaticModInt<M>>,
+    #[allow(dead_code)]
     pub(crate) sum_ie: Vec<StaticModInt<M>>,
 }
 
@@ -1050,7 +1052,7 @@ impl_folding! {
 
 #[cfg(test)]
 mod tests {
-    use crate::modint::ModInt1000000007;
+    use super::ModInt1000000007;
 
     #[test]
     fn static_modint_new() {
diff --git a/src/scc.rs b/src/scc.rs
index 2eff835..d33c15b 100644
--- a/src/scc.rs
+++ b/src/scc.rs
@@ -1,4 +1,4 @@
-use crate::internal_scc;
+use super::internal_scc;
 
 pub struct SccGraph {
     internal: internal_scc::SccGraph,
diff --git a/src/segtree.rs b/src/segtree.rs
index b543aa3..9d6b820 100644
--- a/src/segtree.rs
+++ b/src/segtree.rs
@@ -1,5 +1,5 @@
-use crate::internal_bit::ceil_pow2;
-use crate::internal_type_traits::{BoundedAbove, BoundedBelow, One, Zero};
+use super::internal_bit::ceil_pow2;
+use super::internal_type_traits::{BoundedAbove, BoundedBelow, One, Zero};
 use std::cmp::{max, min};
 use std::convert::Infallible;
 use std::marker::PhantomData;
@@ -238,8 +238,8 @@ where
 
 #[cfg(test)]
 mod tests {
-    use crate::segtree::Max;
-    use crate::Segtree;
+    use super::super::Segtree;
+    use super::Max;
 
     #[test]
     fn test_max_segtree() {
diff --git a/src/twosat.rs b/src/twosat.rs
index ac5f8b6..213d486 100644
--- a/src/twosat.rs
+++ b/src/twosat.rs
@@ -1,4 +1,4 @@
-use crate::internal_scc;
+use super::internal_scc;
 
 pub struct TwoSat {
     n: usize,