Fix day1 build

bt · bt · commit 1b0a7a8f1fc3 · 2025-02-23T16:56:13.000+08:00
diff --git a/src/day1.cpp b/src/day1.cpp
@@ -1,4 +1,5 @@
 #include <algorithm>
+#include <cstdint>
 #include <iostream>
 #include <fstream>
 #include <vector>
