diff --git a/README.md b/README.md
index 065e37a..d9355a4 100644
--- a/README.md
+++ b/README.md
@@ -13,3 +13,7 @@
 - https://github.com/EbTech/rust-algorithms
 - https://github.com/qitoy/rust-library
 - https://github.com/stuart0035/procon-lib-rs
+
+## Our List of Recommended Practice Problems
+
+[gitgud.cc](https://www.gitgud.cc/)
diff --git a/examples/data_structures/deq_agg.rs b/examples/data_structures/deq_agg.rs
index d1f880b..3f2d3b6 100644
--- a/examples/data_structures/deq_agg.rs
+++ b/examples/data_structures/deq_agg.rs
@@ -2,7 +2,7 @@
 
 use proconio::input;
 use programming_team_code_rust::data_structures::deq_agg::DeqAgg;
-use rand::{thread_rng, Rng};
+use rand::{Rng, thread_rng};
 use std::collections::VecDeque;
 
 const MOD: u64 = 998_244_353;
diff --git a/examples/data_structures/range_container_handmade.rs b/examples/data_structures/range_container_handmade.rs
index e26762a..2603b24 100644
--- a/examples/data_structures/range_container_handmade.rs
+++ b/examples/data_structures/range_container_handmade.rs
@@ -1,7 +1,7 @@
 // verification-helper: PROBLEM https://onlinejudge.u-aizu.ac.jp/courses/lesson/2/ITP1/all/ITP1_1_A
 
 use programming_team_code_rust::data_structures::range_container::RangeContainer;
-use rand::{thread_rng, Rng};
+use rand::{Rng, thread_rng};
 use std::collections::BTreeMap;
 
 fn main() {
diff --git a/examples/graphs/bridges_aizu.rs b/examples/graphs/bridges_aizu.rs
index faf58f1..ac16f17 100644
--- a/examples/graphs/bridges_aizu.rs
+++ b/examples/graphs/bridges_aizu.rs
@@ -24,7 +24,7 @@ fn main() {
 
     let mut all_bridges: Vec<(usize, usize)> = vec![];
 
-    for (i, (mut u, mut v)) in edges.iter_mut().enumerate() {
+    for (i, &mut (mut u, mut v)) in edges.iter_mut().enumerate() {
         if is_bridge[i] {
             if u > v {
                 std::mem::swap(&mut u, &mut v);
diff --git a/examples/graphs/cuts_aizu.rs b/examples/graphs/cuts_aizu.rs
index 9f4703b..717ddc4 100644
--- a/examples/graphs/cuts_aizu.rs
+++ b/examples/graphs/cuts_aizu.rs
@@ -30,7 +30,7 @@ fn main() {
     let all_cut_nodes = is_cut
         .iter()
         .enumerate()
-        .filter(|(_, &value)| value)
+        .filter(|&(_, &value)| value)
         .map(|(index, _)| index)
         .collect::<Vec<usize>>();
 
diff --git a/examples/helpers/lis_handmade.rs b/examples/helpers/lis_handmade.rs
index 8815bd8..67d81b8 100644
--- a/examples/helpers/lis_handmade.rs
+++ b/examples/helpers/lis_handmade.rs
@@ -1,7 +1,7 @@
 // verification-helper: PROBLEM https://onlinejudge.u-aizu.ac.jp/courses/lesson/2/ITP1/all/ITP1_1_A
 
 use programming_team_code_rust::helpers::lis::Lis;
-use rand::{thread_rng, Rng};
+use rand::{Rng, thread_rng};
 
 fn lis_quadratic(a: &[i32]) -> usize {
     let n = a.len();
diff --git a/src/data_structures/deq_agg.rs b/src/data_structures/deq_agg.rs
index 6ebd133..44fb5ac 100644
--- a/src/data_structures/deq_agg.rs
+++ b/src/data_structures/deq_agg.rs
@@ -145,7 +145,7 @@ impl<T: Clone, F: Fn(&T, &T) -> T> DeqAgg<T, F> {
         if self.le.is_empty() {
             let mut ary = vec![];
             std::mem::swap(&mut ary, &mut self.ri);
-            self.rebuild((ary.len() + 1) / 2, ary);
+            self.rebuild(ary.len().div_ceil(2), ary);
         }
         self.le.pop().map(|elem| elem.0)
     }
diff --git a/src/graphs/count_paths_per_length.rs b/src/graphs/count_paths_per_length.rs
index 8293b18..f8a7cdc 100644
--- a/src/graphs/count_paths_per_length.rs
+++ b/src/graphs/count_paths_per_length.rs
@@ -1,5 +1,5 @@
 //! # Count the number of paths of each length in a tree
-use crate::graphs::cent_decomp::{cent_decomp, CentDecompDfs};
+use crate::graphs::cent_decomp::{CentDecompDfs, cent_decomp};
 use crate::numbers::fft::fft_multiply;
 
 fn conv(a: &[u64], b: &[u64]) -> Vec<u64> {