Added example for Practice2-L

Author: TonalidadeHidrica

examples/practice2_l_lazy_segment_tree.rs

@@ -0,0 +1,63 @@
+#![allow(clippy::many_single_char_names)]
+use ac_library_rs::{LazySegtree, MapMonoid, Monoid};
+use std::io::Read;
+use std::iter;
+
+struct M;
+impl Monoid for M {
+    type S = (u64, u64, u64);
+    fn identity() -> Self::S {
+        (0, 0, 0)
+    }
+    fn binary_operation((a, b, c): Self::S, (d, e, f): Self::S) -> Self::S {
+        (a + d, b + e, c + f + b * d)
+    }
+}
+struct F;
+impl MapMonoid for F {
+    type M = M;
+    type F = bool;
+
+    fn identity_map() -> Self::F {
+        false
+    }
+    fn mapping(f: Self::F, (a, b, c): <M as Monoid>::S) -> <M as Monoid>::S {
+        if f {
+            // (a + b) * (a + b - 1) / 2 - a * (a - 1) / 2 - b * (b - 1) / 2 - c
+            // = a * b - c
+            (b, a, a * b - c)
+        } else {
+            (a, b, c)
+        }
+    }
+    fn composition(f: Self::F, g: Self::F) -> Self::F {
+        f ^ g
+    }
+}
+
+fn main() {
+    let mut buf = String::new();
+    std::io::stdin().read_to_string(&mut buf).unwrap();
+    let mut input = buf.split_whitespace();
+
+    let n = input.next().unwrap().parse().unwrap();
+    let q = input.next().unwrap().parse().unwrap();
+    let mut segtree: LazySegtree<F> = iter::once((0, 0, 0))
+        .chain(input.by_ref().take(n).map(|s| match s {
+            "0" => (1, 0, 0),
+            "1" => (0, 1, 0),
+            _ => panic!(),
+        }))
+        .collect::<Vec<_>>()
+        .into();
+    for _ in 0..q {
+        let t = input.next().unwrap().parse().unwrap();
+        let l = input.next().unwrap().parse().unwrap();
+        let r: usize = input.next().unwrap().parse().unwrap();
+        match t {
+            1 => segtree.apply_range(l, r + 1, true),
+            2 => println!("{}", segtree.prod(l, r + 1).2),
+            _ => {}
+        }
+    }
+}