From 79253529ea91e6a035671f434e4a759d9db31947 Mon Sep 17 00:00:00 2001
From: rsk0315 <rsk0315@icloud.com>
Date: Mon, 21 Aug 2023 19:12:06 +0900
Subject: [PATCH] fix

---
 crates/ds/bit_set/src/lib.rs  | 2 +-
 crates/math/modint/src/lib.rs | 8 +++++---
 static/nekolib/src/math.rs    | 4 ++--
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/crates/ds/bit_set/src/lib.rs b/crates/ds/bit_set/src/lib.rs
index fef0f4a..473f405 100644
--- a/crates/ds/bit_set/src/lib.rs
+++ b/crates/ds/bit_set/src/lib.rs
@@ -63,7 +63,7 @@ impl BitSet {
     }
 
     #[must_use]
-    pub fn contains(&mut self, index: usize) -> bool {
+    pub fn contains(&self, index: usize) -> bool {
         check_bounds(index, self.capacity);
 
         let (wi, bi) = (index / WORD_SIZE, index % WORD_SIZE);
diff --git a/crates/math/modint/src/lib.rs b/crates/math/modint/src/lib.rs
index dafd4ec..afc394b 100644
--- a/crates/math/modint/src/lib.rs
+++ b/crates/math/modint/src/lib.rs
@@ -218,12 +218,13 @@ impl Barrett {
 
     fn mul(&self, a: u32, b: u32) -> u32 {
         let m = self.m.load(atomic::Ordering::SeqCst);
-        let im = self.m.load(atomic::Ordering::SeqCst);
+        let im = self.im.load(atomic::Ordering::SeqCst);
 
         let z = a as u64 * b as u64;
         let x = ((z as u128 * im as u128) >> 64) as u64;
-        let v = z.wrapping_sub(x.wrapping_mul(m as u64)) as u32;
-        if m <= v { v.wrapping_add(m) } else { v }
+        let y = x.wrapping_mul(m as u64);
+        let v = z.wrapping_sub(y) as u32;
+        v.wrapping_add(if z < y { m } else { 0 })
     }
 }
 
@@ -509,6 +510,7 @@ fn sanity_check() {
     type Md = DynamicModInt<DefaultId>;
     Md::set_modulus(10);
     assert_eq!(Md::new(5) + Md::new(7), Md::new(2));
+    assert_eq!(Md::new(3) * Md::new(4), Md::new(2));
 
     Md::set_modulus(4);
     assert_eq!(Md::new(5) + Md::new(7), Md::new(0));
diff --git a/static/nekolib/src/math.rs b/static/nekolib/src/math.rs
index e34908a..3243a4a 100644
--- a/static/nekolib/src/math.rs
+++ b/static/nekolib/src/math.rs
@@ -129,8 +129,8 @@ pub use mod_recip_table_::mod_recip_table_prime;
 pub use mod_tetration::ModTetration;
 #[doc(inline)]
 pub use modint::{
-    Mod1000000007, Mod998244353, ModInt1000000007, ModInt998244353, ModIntBase,
-    Modulus, StaticModInt,
+    DefaultId, DynamicModInt, Mod1000000007, Mod998244353, ModInt1000000007,
+    ModInt998244353, ModIntBase, Modulus, StaticModInt,
 };
 #[doc(inline)]
 pub use prime_pi_::prime_pi;