fix

rsk0315 · Aug 21, 2023 · 7925352 · 7925352
1 parent 16f050c
commit 7925352
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Showing 3 changed files with 8 additions and 6 deletions.
diff --git 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
@@ -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
@@ -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;