From 2b60b4e486945ac1bf0abb1beb0a6b2fb49061f1 Mon Sep 17 00:00:00 2001
From: megakabi <jakevin@megatechnology.com>
Date: Wed, 26 Nov 2025 18:10:14 +0800
Subject: [PATCH] refactor: optimize vector initialization with size hints in
 state and precompile modules

---
 crates/database/src/states/state.rs     |  8 +++++---
 crates/precompile/src/bls12_381/blst.rs | 10 ++++++----
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/crates/database/src/states/state.rs b/crates/database/src/states/state.rs
index 22f8263343..756dab1b68 100644
--- a/crates/database/src/states/state.rs
+++ b/crates/database/src/states/state.rs
@@ -122,9 +122,11 @@ impl<DB: Database> State<DB> {
         addresses: impl IntoIterator<Item = Address>,
     ) -> Result<Vec<u128>, DB::Error> {
         // Make transition and update cache state
-        let mut transitions = Vec::new();
-        let mut balances = Vec::new();
-        for address in addresses {
+        let addresses_iter = addresses.into_iter();
+        let (lower, _) = addresses_iter.size_hint();
+        let mut transitions = Vec::with_capacity(lower);
+        let mut balances = Vec::with_capacity(lower);
+        for address in addresses_iter {
             let original_account = self.load_cache_account(address)?;
             let (balance, transition) = original_account.drain_balance();
             balances.push(balance);
diff --git a/crates/precompile/src/bls12_381/blst.rs b/crates/precompile/src/bls12_381/blst.rs
index d20c7af561..6200382a25 100644
--- a/crates/precompile/src/bls12_381/blst.rs
+++ b/crates/precompile/src/bls12_381/blst.rs
@@ -681,8 +681,9 @@ pub(crate) fn map_fp2_to_g2_bytes(
 pub(crate) fn p1_msm_bytes(
     point_scalar_pairs: impl Iterator<Item = Result<G1PointScalar, crate::PrecompileError>>,
 ) -> Result<[u8; G1_LENGTH], crate::PrecompileError> {
-    let mut g1_points = Vec::new();
-    let mut scalars = Vec::new();
+    let (lower, _) = point_scalar_pairs.size_hint();
+    let mut g1_points = Vec::with_capacity(lower);
+    let mut scalars = Vec::with_capacity(lower);
 
     // Parse all points and scalars
     for pair_result in point_scalar_pairs {
@@ -718,8 +719,9 @@ pub(crate) fn p1_msm_bytes(
 pub(crate) fn p2_msm_bytes(
     point_scalar_pairs: impl Iterator<Item = Result<G2PointScalar, crate::PrecompileError>>,
 ) -> Result<[u8; G2_LENGTH], crate::PrecompileError> {
-    let mut g2_points = Vec::new();
-    let mut scalars = Vec::new();
+    let (lower, _) = point_scalar_pairs.size_hint();
+    let mut g2_points = Vec::with_capacity(lower);
+    let mut scalars = Vec::with_capacity(lower);
 
     // Parse all points and scalars
     for pair_result in point_scalar_pairs {