From 05e2c0009e46be16ad4cfd10cd1dac0393f44b38 Mon Sep 17 00:00:00 2001
From: mousecrusher2 <95418154+mousecrusher2@users.noreply.github.com>
Date: Tue, 13 Feb 2024 22:19:43 +0900
Subject: [PATCH 1/2] fix FromIterator for Segtree
---
src/segtree.rs | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)
diff --git a/src/segtree.rs b/src/segtree.rs
index e79c74e..1b7113c 100644
--- a/src/segtree.rs
+++ b/src/segtree.rs
@@ -137,22 +137,8 @@ impl<M: Monoid> From<Vec<M::S>> for Segtree<M> {
}
impl<M: Monoid> FromIterator<M::S> for Segtree<M> {
fn from_iter<T: IntoIterator<Item = M::S>>(iter: T) -> Self {
- let iter = iter.into_iter();
- let n = iter.size_hint().0;
- let log = ceil_pow2(n as u32) as usize;
- let size = 1 << log;
- let mut d = Vec::with_capacity(size * 2);
- d.extend(
- std::iter::repeat_with(M::identity)
- .take(size)
- .chain(iter)
- .chain(std::iter::repeat_with(M::identity).take(size - n)),
- );
- let mut ret = Segtree { n, size, log, d };
- for i in (1..size).rev() {
- ret.update(i);
- }
- ret
+ let v = iter.into_iter().collect::<Vec<_>>();
+ v.into()
}
}
impl<M: Monoid> Segtree<M> {
@@ -353,6 +339,18 @@ mod tests {
check_segtree(&internal, &segtree);
}
+ #[test]
+ fn test_segtree_fromiter() {
+ let v = vec![1, 4, 1, 4, 2, 1, 3, 5, 6];
+ let base = v
+ .iter()
+ .copied()
+ .filter(|&x| x % 2 == 0)
+ .collect::<Vec<_>>();
+ let segtree: Segtree<Max<_>> = v.iter().copied().filter(|&x| x % 2 == 0).collect();
+ check_segtree(&base, &segtree);
+ }
+
//noinspection DuplicatedCode
fn check_segtree(base: &[i32], segtree: &Segtree<Max<i32>>) {
let n = base.len();
From 23ccb58a273cc27688ae55f91ab3d5eb731903b1 Mon Sep 17 00:00:00 2001
From: mousecrusher2 <95418154+mousecrusher2@users.noreply.github.com>
Date: Thu, 15 Feb 2024 04:02:13 +0900
Subject: [PATCH 2/2] remove unnecessary vec!
---
src/segtree.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/segtree.rs b/src/segtree.rs
index 1b7113c..0b76b40 100644
--- a/src/segtree.rs
+++ b/src/segtree.rs
@@ -341,7 +341,7 @@ mod tests {
#[test]
fn test_segtree_fromiter() {
- let v = vec![1, 4, 1, 4, 2, 1, 3, 5, 6];
+ let v = [1, 4, 1, 4, 2, 1, 3, 5, 6];
let base = v
.iter()
.copied()