From 3c654f38eb623e413238a596ee3397d0139a1dd1 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Fri, 5 Aug 2016 18:15:34 +1200
Subject: [PATCH] Eliminate probably duplicates in final round

This is more likely to eliminate valid solutions than doing so in intermediate
rounds, but the probability is still very low.
---
 src/crypto/equihash.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/crypto/equihash.cpp b/src/crypto/equihash.cpp
index d2686a263..9c018d72f 100644
--- a/src/crypto/equihash.cpp
+++ b/src/crypto/equihash.cpp
@@ -487,8 +487,12 @@ bool Equihash<N,K>::OptimisedSolve(const eh_HashState& base_state,
 
                 for (int l = 0; l < j - 1; l++) {
                     for (int m = l + 1; m < j; m++) {
-                        TruncatedStepRow<FinalTruncatedWidth> res(Xt[i+l], Xt[i+m], hashLen, lenIndices, 0);
-                        partialSolns.push_back(res.GetTruncatedIndices(hashLen, 2*lenIndices));
+                        TruncatedStepRow<FinalTruncatedWidth> res(Xt[i+l], Xt[i+m],
+                                                                  hashLen, lenIndices, 0);
+                        auto soln = res.GetTruncatedIndices(hashLen, 2*lenIndices);
+                        if (!IsProbablyDuplicate<soln_size>(soln, 2*lenIndices)) {
+                            partialSolns.push_back(soln);
+                        }
                     }
                 }