do it this way actually

Author: lrvideckis

tests/library_checker_aizu_tests/dsu/dsu_weighted_aizu.test.cpp

@@ -13,20 +13,18 @@ int main() {
     int type, u, v;
     cin >> type >> u >> v;
     if (type == 0) {
-      assert(dsu.size(u) == dsu_w.size(u));
-      assert(dsu.size(v) == dsu_w.size(v));
       int w;
       cin >> w;
       dsu_w.join(u, v, w);
       dsu.join(u, v);
       assert(dsu.size(u) == dsu_w.size(u));
       assert(dsu.size(v) == dsu_w.size(v));
     } else {
-      assert(dsu.size(u) == dsu_w.size(u));
-      assert(dsu.size(v) == dsu_w.size(v));
       ll curr_diff = dsu_w.diff(u, v);
       if (curr_diff == 1e18) cout << "?\n";
       else cout << dsu_w.diff(u, v) << '\n';
+      assert(dsu.size(u) == dsu_w.size(u));
+      assert(dsu.size(v) == dsu_w.size(v));
     }
   }
   return 0;

tests/library_checker_aizu_tests/dsu/dsu_weighted_lib_checker.test.cpp

@@ -14,8 +14,6 @@ int main() {
     int type, u, v;
     cin >> type >> u >> v;
     if (type == 0) {
-      assert(dsu.size(u) == dsu_w.size(u));
-      assert(dsu.size(v) == dsu_w.size(v));
       int w;
       cin >> w;
       ll curr_diff = dsu_w.diff(u, v);
@@ -29,11 +27,11 @@ int main() {
       assert(dsu.size(u) == dsu_w.size(u));
       assert(dsu.size(v) == dsu_w.size(v));
     } else {
-      assert(dsu.size(u) == dsu_w.size(u));
-      assert(dsu.size(v) == dsu_w.size(v));
       ll curr_diff = dsu_w.diff(u, v);
       if (curr_diff == 1e18) cout << -1 << '\n';
       else cout << (curr_diff % mod + mod) % mod << '\n';
+      assert(dsu.size(u) == dsu_w.size(u));
+      assert(dsu.size(v) == dsu_w.size(v));
     }
   }
   return 0;