diff --git a/backtracking/subset_sum.cpp b/backtracking/subset_sum.cpp
index fad820920..bcc8ae744 100644
--- a/backtracking/subset_sum.cpp
+++ b/backtracking/subset_sum.cpp
@@ -10,6 +10,7 @@
  */
 
 #include <cassert>   /// for assert
+#include <cstdint>   /// for integral typedefs
 #include <iostream>  /// for IO operations
 #include <vector>    /// for std::vector