diff --git a/code/ryzom/tools/assoc_mem/tree.cpp b/code/ryzom/tools/assoc_mem/tree.cpp
index c706231e1..3753a147c 100644
--- a/code/ryzom/tools/assoc_mem/tree.cpp
+++ b/code/ryzom/tools/assoc_mem/tree.cpp
@@ -18,6 +18,7 @@
 #include <map>
 #include <stdio.h>
 #include <iostream>
+#include <algorithm>
 
 #include "tree.h"
 #include "cond_node.h"