diff --git a/internal/ceres/summary_utils.cc b/internal/ceres/summary_utils.cc
index 29e272e..243030c 100644
--- a/internal/ceres/summary_utils.cc
+++ b/internal/ceres/summary_utils.cc
@@ -28,6 +28,7 @@
 //
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 
+#include <algorithm>
 #include "ceres/summary_utils.h"
 #include "ceres/program.h"
 #include "ceres/solver.h"