diff --git a/c++/algorithm/distancepath.cpp b/c++/algorithm/distancepath.cpp
index 3806150..8ad90d4 100644
--- a/c++/algorithm/distancepath.cpp
+++ b/c++/algorithm/distancepath.cpp
@@ -96,7 +96,7 @@ int8_t DistancePath::process(Image* input, Image* output) {
     // swap list to get new input queue
     std::swap(last, next);
     if (iteration > 10000) break;
-  }  while (next->size() > 0);
+  }  while (last->size() > 0);
 
   printf("iterations: %i\n", iteration);
   // find max value