Update template.cpp

Author: JJCUBER

content/contest/template.cpp

@@ -3,7 +3,7 @@ using namespace std;
 
 #define rep(i, a, b) for(int i = a; i < (b); ++i)
 #define all(x) begin(x), end(x)
-#define sz(x) (int)size(x)
+#define sz(x) (int)::size(x)
 typedef long long ll;
 typedef pair<int, int> pii;
 typedef vector<int> vi;