From f69062ce95fa061e85550e37486326e660177d2b Mon Sep 17 00:00:00 2001
From: Asim Shaik <asimshaik564@gmail.com>
Date: Thu, 6 Nov 2025 22:07:57 +0530
Subject: [PATCH] allow initializing MerkleTree with caller-provided
 precomputed zero hashes

Signed-off-by: Asim Shaik <asimshaik564@gmail.com>
---
 src/tree.rs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/tree.rs b/src/tree.rs
index 99cc585..eeee626 100644
--- a/src/tree.rs
+++ b/src/tree.rs
@@ -84,6 +84,20 @@ where
         }
     }
 
+    /// Initialize Merkle tree with caller-provided precomputed zero hashes
+    /// precomputed[i] must be the zero hash at level i (0 = leaf, DEPTH-1 = top)
+    pub fn with_precomputed_zeros(hasher: H, store: S, precomputed: [Node; DEPTH]) -> Self {
+        let zeros = Zeros {
+            front: precomputed,
+            last: hasher.hash(&precomputed[DEPTH - 1], &precomputed[DEPTH - 1]),
+        };
+        Self {
+            hasher,
+            store,
+            zeros,
+        }
+    }
+
     pub fn add_leaves(&mut self, leaves: &[Node]) -> Result<(), MerkleError> {
         // Early return
         if leaves.is_empty() {