From ca56617ef144fc54c751912849cd37e5b20b4f17 Mon Sep 17 00:00:00 2001
From: Mason Liang <mason@scroll.io>
Date: Sun, 19 Nov 2023 14:22:56 -0500
Subject: [PATCH] Only assign final row first time assign is called

---
 src/mpt.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/mpt.rs b/src/mpt.rs
index 12ce206c..1b024f71 100644
--- a/src/mpt.rs
+++ b/src/mpt.rs
@@ -121,9 +121,17 @@ impl MptCircuitConfig {
         let randomness = self.rlc_randomness.value(layouter);
         let (u32s, u64s, u128s, frs) = byte_representations(proofs);
 
+        let mut is_first_call = true;
+
         layouter.assign_region(
             || "mpt circuit",
-            |mut region| {
+            move |mut region| {
+                if is_first_call {
+                    is_first_call = false;
+                    self.selector.enable(&mut region, n_rows - 1);
+                    return Ok(())
+                }
+
                 for offset in 1..n_rows {
                     self.selector.enable(&mut region, offset);
                 }