1 files changed, 29 insertions, 0 deletions
diff --git a/mteval/levenshtein.h b/mteval/levenshtein.h
new file mode 100644
index 00000000..13a97047
--- /dev/null
+++ b/mteval/levenshtein.h
@@ -0,0 +1,29 @@
+#ifndef _LEVENSHTEIN_H_
+#define _LEVENSHTEIN_H_
+
+namespace cdec {
+
+template <typename V>
+inline unsigned LevenshteinDistance(const V& a, const V& b) {
+  const unsigned m = a.size(), n = b.size();
+  std::vector<unsigned> edit((m + 1) * 2);
+  for (unsigned i = 0; i <= n; i++) {
+    for (unsigned j = 0; j <= m; j++) {
+      if (i == 0)
+        edit[j] = j;
+      else if (j == 0)
+        edit[(i % 2) * (m + 1)] = i;
+      else
+        edit[(i % 2) * (m + 1) + j] = std::min(std::min(
+                                edit[(i % 2) * (m + 1) + j - 1] + 1,
+                                edit[((i - 1) % 2) * (m + 1) + j] + 1),
+                                edit[((i - 1) % 2) * (m + 1) + (j - 1)] 
+                                    + (a[j - 1] == b[i - 1] ? 0 : 1));
+    }
+  }
+  return edit[(n % 2) * (m + 1) + m];
+}
+
+}
+
+#endif