From cb620bc55a28ca94649ea89d1111deab6562ebf0 Mon Sep 17 00:00:00 2001
From: wborgeaud <williamborgeaud@gmail.com>
Date: Thu, 29 Sep 2022 16:32:41 +0200
Subject: [PATCH] Simplify `num_ctl_zs`

---
 evm/src/cross_table_lookup.rs | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/evm/src/cross_table_lookup.rs b/evm/src/cross_table_lookup.rs
index 1b42801f..b5223e50 100644
--- a/evm/src/cross_table_lookup.rs
+++ b/evm/src/cross_table_lookup.rs
@@ -193,18 +193,12 @@ impl<F: Field> CrossTableLookup<F> {
     }
 
     pub(crate) fn num_ctl_zs(ctls: &[Self], table: Table, num_challenges: usize) -> usize {
-        let mut ans = 0;
+        let mut num_ctls = 0;
         for ctl in ctls {
-            ans += ctl
-                .looking_tables
-                .iter()
-                .filter_map(|twc| (twc.table == table).then_some(num_challenges))
-                .sum::<usize>();
-            ans += (ctl.looked_table.table == table)
-                .then_some(num_challenges)
-                .unwrap_or_default();
+            let all_tables = std::iter::once(&ctl.looked_table).chain(&ctl.looking_tables);
+            num_ctls += all_tables.filter(|twc| twc.table == table).count();
         }
-        ans
+        num_ctls * num_challenges
     }
 }