diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 
 `filediff` is a Haskell library for creating diffs, and applying diffs to files and directories.
 
+[![Build Status](https://travis-ci.org/bgwines/filediff.svg?branch=master)](https://travis-ci.org/bgwines/filediff) [![Hackage](https://img.shields.io/hackage/v/filediff.svg)](https://hackage.haskell.org/package/filediff) [![Coverage Status](https://coveralls.io/repos/bgwines/filediff/badge.svg?branch=master)](https://coveralls.io/r/bgwines/filediff?branch=master)
+
 ## Testing
 
     cabal configure --enable tests && build && cabal test
@@ -9,6 +11,4 @@
 ## Found an issue?
 
 Don't hesitate to let me know / issue a PR!
-
-[![Build Status](https://travis-ci.org/bgwines/filediff.svg?branch=master)](https://travis-ci.org/bgwines/filediff)
 
diff --git a/filediff.cabal b/filediff.cabal
--- a/filediff.cabal
+++ b/filediff.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                filediff
-version:             1.0.0.1
+version:             1.0.0.2
 synopsis:            Diffing and patching module
 description:         `filediff` is a Haskell library for creating diffs, and applying diffs to files and directories.
 homepage:            https://github.com/bgwines/filediff
@@ -32,4 +32,4 @@
     main-is:    Tests/test-filediff.hs
     build-depends: base >=4.7 && <4.8, tasty, tasty-hunit, mtl, time, directory, either, transformers, filediff, text
     default-language:    Haskell2010
-    --GHC-Options:      -fhpc -hpcdir dist/hpc/filediff-1.0
+    GHC-Options:      -fhpc -hpcdir dist/hpc/mix/test-filediff
diff --git a/src/Filediff.hs b/src/Filediff.hs
--- a/src/Filediff.hs
+++ b/src/Filediff.hs
@@ -223,7 +223,7 @@
     (getProgressiveIndicesToAdd common b)
     where
         common :: [a]
-        common = longestCommonSubsequence a b
+        common = longestCommonSubsequenceWrapper a b
 
         -- | > λ add
         --   > [(0,"w"),(3,"x"),(4,"y")]
@@ -260,6 +260,31 @@
                 else d : insertAtProgressiveIndices' (succ curr) src dest'
 
 -- all functions below are not exposed
+
+-- don't hit the memotable if not necessary
+longestCommonSubsequenceWrapper :: forall a. (MemoTable a, Eq a) => [a] -> [a] -> [a]
+longestCommonSubsequenceWrapper xs ys =
+    if xs == ys
+        then xs -- (WLOG) don't want to return xs ++ xs
+        else commonPrefix ++ longestCommonSubsequence xs' ys' ++ commonSuffix
+    where
+        commonPrefix :: [a]
+        commonPrefix = getCommonPrefix xs ys
+
+        commonSuffix :: [a]
+        commonSuffix = reverse (getCommonPrefix (reverse xs) (reverse ys))
+
+        getCommonPrefix :: [a] -> [a] -> [a]
+        getCommonPrefix as bs = map fst . takeWhile (uncurry (==)) $ zip as bs
+
+        getMiddle :: [a] -> [a]
+        getMiddle elems = take (length elems - length commonPrefix - length commonSuffix) . drop (length commonPrefix) $ elems
+
+        xs' :: [a]
+        xs' = getMiddle xs
+
+        ys' :: [a]
+        ys' = getMiddle ys
 
 -- optimization: hash lines
 -- | Compute the longest common (potentially noncontiguous) subsequence