diff --git a/docs/CONTRIBUTORS b/docs/CONTRIBUTORS
index 38d913faa..6b55ee4dc 100644
--- a/docs/CONTRIBUTORS
+++ b/docs/CONTRIBUTORS
@@ -31,6 +31,7 @@ Graham Rushton
 Harald Heckmann
 Howard Su
 Huang Rui
+HungMingWu
 HyungKi Jeong
 Iru Cai
 Ivan Vnučec
diff --git a/src/V3TSP.cpp b/src/V3TSP.cpp
index 371bbb892..4032a0622 100644
--- a/src/V3TSP.cpp
+++ b/src/V3TSP.cpp
@@ -141,7 +141,7 @@ private:
     }
 
     struct EdgeListCmp final {
-        bool operator()(const EdgeList* ap, const EdgeList* bp) {
+        bool operator()(const EdgeList* ap, const EdgeList* bp) const {
             // Simply compare heads
             return edgeCmp(bp->back(), ap->back());
         }