diff --git a/dynamic_programming/word_break.cpp b/dynamic_programming/word_break.cpp
index f1e219001..1ccdd05a4 100644
--- a/dynamic_programming/word_break.cpp
+++ b/dynamic_programming/word_break.cpp
@@ -33,6 +33,7 @@
 #include <string>
 #include <unordered_set>
 #include <vector>
+#include <cassert>
 
 /**
  * @namespace dynamic_programming