diff --git a/src/mmc_highorder.cpp b/src/mmc_highorder.cpp
index 6ad1c1a..411f430 100644
--- a/src/mmc_highorder.cpp
+++ b/src/mmc_highorder.cpp
@@ -33,6 +33,7 @@
 #include <list>
 #include <vector>
 #include <unordered_map>
+#include <array>
 #include <algorithm>
 #include <string>
 #include <string.h>
@@ -114,7 +115,7 @@ class Vec3Hash {
         std::size_t seed = 3;
 
         for (int i = 0; i < 3; i++) {
-            seed ^= vec.at(i) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
+            seed ^= vec[i] + 0x9e3779b9 + (seed << 6) + (seed >> 2);
         }
 
         return seed;