Implement segtree

examples/practice2_j_segment_tree.rs

@@ -0,0 +1,35 @@
+use ac_library_rs::{Max, Segtree};
+use std::io::Read;
+
+fn main() {
+    let mut buf = String::new();
+    std::io::stdin().read_to_string(&mut buf).unwrap();
+    let mut input = buf.split_whitespace();
+
+    let n: usize = input.next().unwrap().parse().unwrap();
+    let q: usize = input.next().unwrap().parse().unwrap();
+    let mut segtree = Segtree::<Max<i32>>::new(n + 1);
+    for i in 1..=n {
+        segtree.set(i, input.next().unwrap().parse().unwrap());
+    }
+    for _ in 0..q {
+        match input.next().unwrap().parse().unwrap() {
+            1 => {
+                let x = input.next().unwrap().parse().unwrap();
+                let v = input.next().unwrap().parse().unwrap();
+                segtree.set(x, v);
+            }
+            2 => {
+                let l = input.next().unwrap().parse().unwrap();
+                let r: usize = input.next().unwrap().parse().unwrap();
+                println!("{}", segtree.prod(l, r + 1));
+            }
+            3 => {
+                let x = input.next().unwrap().parse().unwrap();
+                let v = input.next().unwrap().parse().unwrap();
+                println!("{}", segtree.max_right(x, |a| a < &v))
+            }
+            _ => {}
+        }
+    }
+}

src/internal_type_traits.rs

@@ -52,37 +52,65 @@ pub trait Integral:
     + fmt::Debug
     + fmt::Binary
     + fmt::Octal
+    + Zero
+    + One
+    + BoundedBelow
+    + BoundedAbove
 {
+}
+
+/// Class that has additive identity element
+pub trait Zero {
+    /// The additive identity element
     fn zero() -> Self;
+}
+
+/// Class that has multiplicative identity element
+pub trait One {
+    /// The multiplicative identity element
     fn one() -> Self;
+}
+
+pub trait BoundedBelow {
     fn min_value() -> Self;
+}
+
+pub trait BoundedAbove {
     fn max_value() -> Self;
 }
 
 macro_rules! impl_integral {
     ($($ty:ty),*) => {
         $(
-            impl Integral for $ty {
+            impl Zero for $ty {
                 #[inline]
                 fn zero() -> Self {
                     0
                 }
+            }
 
+            impl One for $ty {
                 #[inline]
                 fn one() -> Self {
                     1
                 }
+            }
 
+            impl BoundedBelow for $ty {
                 #[inline]
                 fn min_value() -> Self {
                     Self::min_value()
                 }
+            }
 
+            impl BoundedAbove for $ty {
                 #[inline]
                 fn max_value() -> Self {
                     Self::max_value()
                 }
             }
+
+            impl Integral for $ty {}
         )*
     };
 }

src/lib.rs

@@ -28,6 +28,7 @@ pub use modint::{
     ModInt998244353, Modulus, RemEuclidU32, StaticModInt,
 };
 pub use scc::SccGraph;
+pub use segtree::{Additive, Max, Min, Monoid, Multiplicative, Segtree};
 pub use string::{
     lcp_array, lcp_array_arbitrary, suffix_array, suffix_array_arbitrary, suffix_array_manual,
     z_algorithm, z_algorithm_arbitrary,