From eb75bab81b34a975f4a197188d53f5cc9e0799c2 Mon Sep 17 00:00:00 2001
From: Alexey <peretsmobil@gmail.com>
Date: Mon, 15 Jul 2019 18:33:46 +0300
Subject: [PATCH] other way to lookup a root

---
 contracts/MerkleTreeWithHistory.sol | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/contracts/MerkleTreeWithHistory.sol b/contracts/MerkleTreeWithHistory.sol
index 587d3aa..28aedbe 100644
--- a/contracts/MerkleTreeWithHistory.sol
+++ b/contracts/MerkleTreeWithHistory.sol
@@ -89,12 +89,26 @@ contract MerkleTreeWithHistory {
         return true;
       }
     }
+
+    // process the rest of roots
     for(i = ROOT_HISTORY_SIZE - 1; i > current_root; i--) {
       if (root == _roots[i]) {
         return true;
       }
     }
     return false;
+
+    // or we can do that in other way
+    //   uint256 i = _current_root;
+    //   do {
+    //       if (root == _roots[i]) {
+    //           return true;
+    //       }
+    //       if (i == 0) {
+    //           i = ROOT_HISTORY_SIZE;
+    //       }
+    //       i--;
+    //   } while (i != _current_root);
   }
 
   function getLastRoot() public view returns(uint256) {