Merge remote-tracking branch 'origin/dev' into naming-consistency

# Conflicts:
#	library/data_structures_[l,r)/uncommon/priority_queue_of_updates.hpp

Author: Cameron Custer

.verify-helper/timestamps.remote.json

@@ -1,17 +1,17 @@
 {
 "tests/library_checker_aizu_tests/convolution/gcd_convolution.test.cpp": "2025-08-28 13:19:16 -0600",
 "tests/library_checker_aizu_tests/convolution/lcm_convolution.test.cpp": "2025-08-28 13:19:16 -0600",
-"tests/library_checker_aizu_tests/convolution/min_plus_convolution.test.cpp": "2026-04-12 16:21:27 -0600",
+"tests/library_checker_aizu_tests/convolution/min_plus_convolution.test.cpp": "2026-07-06 09:57:36 -0700",
 "tests/library_checker_aizu_tests/convolution/xor_convolution.test.cpp": "2026-03-06 12:17:28 -0700",
 "tests/library_checker_aizu_tests/data_structures/binary_search_example.test.cpp": "2024-11-18 10:51:39 -0600",
 "tests/library_checker_aizu_tests/data_structures/binary_trie.test.cpp": "2026-01-18 02:20:40 +0000",
-"tests/library_checker_aizu_tests/data_structures/bit.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/data_structures/bit_inc.test.cpp": "2026-04-06 12:17:32 -0600",
-"tests/library_checker_aizu_tests/data_structures/bit_inc_walk.test.cpp": "2026-04-06 12:17:32 -0600",
-"tests/library_checker_aizu_tests/data_structures/bit_ordered_set.test.cpp": "2026-04-06 12:17:32 -0600",
-"tests/library_checker_aizu_tests/data_structures/bit_rupq.test.cpp": "2026-04-06 12:17:32 -0600",
-"tests/library_checker_aizu_tests/data_structures/bit_rurq.test.cpp": "2026-04-06 12:17:32 -0600",
-"tests/library_checker_aizu_tests/data_structures/bit_walk.test.cpp": "2026-04-26 11:38:07 -0600",
+"tests/library_checker_aizu_tests/data_structures/bit.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/data_structures/bit_inc.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/data_structures/bit_inc_walk.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/data_structures/bit_ordered_set.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/data_structures/bit_rupq.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/data_structures/bit_rurq.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/data_structures/bit_walk.test.cpp": "2026-07-06 09:26:00 -0700",
 "tests/library_checker_aizu_tests/data_structures/deque.test.cpp": "2026-01-18 02:20:40 +0000",
 "tests/library_checker_aizu_tests/data_structures/deque_index.test.cpp": "2026-01-18 02:20:40 +0000",
 "tests/library_checker_aizu_tests/data_structures/deque_op.test.cpp": "2026-01-18 02:20:40 +0000",
@@ -33,7 +33,7 @@
 "tests/library_checker_aizu_tests/data_structures/permutation_tree.test.cpp": "2026-05-24 23:00:07 -0500",
 "tests/library_checker_aizu_tests/data_structures/persistent_queue_tree.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/data_structures/persistent_seg_tree.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/data_structures/pq_ds_undo_sliding_window.test.cpp": "2026-01-18 02:20:40 +0000",
+"tests/library_checker_aizu_tests/data_structures/pq_ds_undo_sliding_window.test.cpp": "2026-07-06 09:26:00 -0700",
 "tests/library_checker_aizu_tests/data_structures/rmq_linear.test.cpp": "2026-05-24 23:00:07 -0500",
 "tests/library_checker_aizu_tests/data_structures/rmq_sparse_table.test.cpp": "2026-05-24 23:00:07 -0500",
 "tests/library_checker_aizu_tests/data_structures/rmq_sparse_table_inc.test.cpp": "2026-01-18 11:15:41 +0000",
@@ -55,33 +55,33 @@
 "tests/library_checker_aizu_tests/dsu/range_parallel_dsu.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/flow/hungarian.test.cpp": "2024-11-17 14:04:03 -0600",
 "tests/library_checker_aizu_tests/flow/min_cost_max_flow.test.cpp": "2026-04-06 14:41:55 -0600",
-"tests/library_checker_aizu_tests/graphs/bcc_callback_aizu_bcc.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/graphs/bcc_callback_aizu_two_edge_cc.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/graphs/bcc_callback_lib_checker_bcc.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/graphs/bcc_callback_lib_checker_two_cc.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/graphs/biconnected_components.test.cpp": "2026-04-26 11:38:07 -0600",
+"tests/library_checker_aizu_tests/graphs/bcc_callback_aizu_bcc.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/graphs/bcc_callback_aizu_two_edge_cc.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/graphs/bcc_callback_lib_checker_bcc.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/graphs/bcc_callback_lib_checker_two_cc.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/graphs/biconnected_components.test.cpp": "2026-07-06 09:57:36 -0700",
 "tests/library_checker_aizu_tests/graphs/connected_components_of_complement_graph.test.cpp": "2026-04-06 14:41:55 -0600",
 "tests/library_checker_aizu_tests/graphs/dijkstra_aizu.test.cpp": "2026-04-06 14:41:55 -0600",
 "tests/library_checker_aizu_tests/graphs/dijkstra_lib_checker.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/graphs/directed_cycle.test.cpp": "2026-04-12 16:21:27 -0600",
+"tests/library_checker_aizu_tests/graphs/directed_cycle.test.cpp": "2026-07-06 09:57:36 -0700",
 "tests/library_checker_aizu_tests/graphs/enumerate_triangles.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/graphs/euler_walk_directed.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/graphs/euler_walk_undirected.test.cpp": "2026-04-12 16:21:27 -0600",
+"tests/library_checker_aizu_tests/graphs/euler_walk_directed.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/graphs/euler_walk_undirected.test.cpp": "2026-07-06 09:57:36 -0700",
 "tests/library_checker_aizu_tests/graphs/hopcroft_karp_aizu.test.cpp": "2026-05-01 11:34:51 -0600",
 "tests/library_checker_aizu_tests/graphs/hopcroft_karp_lib_checker.test.cpp": "2026-05-01 11:34:51 -0600",
 "tests/library_checker_aizu_tests/graphs/mst.test.cpp": "2026-01-22 10:08:22 -0700",
-"tests/library_checker_aizu_tests/graphs/offline_incremental_scc.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/graphs/strongly_connected_components_aizu.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/graphs/strongly_connected_components_lib_checker.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/graphs/two_edge_components.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/handmade_tests/count_paths.test.cpp": "2026-04-27 08:17:20 -0600",
+"tests/library_checker_aizu_tests/graphs/offline_incremental_scc.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/graphs/strongly_connected_components_aizu.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/graphs/strongly_connected_components_lib_checker.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/graphs/two_edge_components.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/handmade_tests/count_paths.test.cpp": "2026-07-06 09:57:36 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/dsu.test.cpp": "2026-01-22 10:08:22 -0700",
-"tests/library_checker_aizu_tests/handmade_tests/edge_cd_small_trees.test.cpp": "2026-04-27 08:17:20 -0600",
+"tests/library_checker_aizu_tests/handmade_tests/edge_cd_small_trees.test.cpp": "2026-07-06 09:57:36 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/fib_matrix_expo.test.cpp": "2026-01-28 21:48:16 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/functional_graph.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/handmade_tests/hilbert_mos.test.cpp": "2026-01-18 02:20:40 +0000",
 "tests/library_checker_aizu_tests/handmade_tests/kd_bit.test.cpp": "2026-02-19 18:06:52 -0700",
-"tests/library_checker_aizu_tests/handmade_tests/kth_par.test.cpp": "2026-06-27 18:29:52 -0500",
+"tests/library_checker_aizu_tests/handmade_tests/kth_par.test.cpp": "2026-07-06 09:57:36 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/manacher.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/handmade_tests/merge_st_and_wavelet.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/handmade_tests/mobius.test.cpp": "2025-02-10 14:50:36 -0700",
@@ -90,7 +90,7 @@
 "tests/library_checker_aizu_tests/handmade_tests/permutation_tree_small.test.cpp": "2026-05-24 23:00:07 -0500",
 "tests/library_checker_aizu_tests/handmade_tests/rmq_small_n.test.cpp": "2026-05-24 23:00:07 -0500",
 "tests/library_checker_aizu_tests/handmade_tests/sa_find_subarray.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/handmade_tests/seg_tree_find.test.cpp": "2026-04-26 11:38:07 -0600",
+"tests/library_checker_aizu_tests/handmade_tests/seg_tree_find.test.cpp": "2026-07-06 09:26:00 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/seg_tree_find_small.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/handmade_tests/seg_tree_midpoint.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/handmade_tests/xor_basis_walk.test.cpp": "2026-03-08 15:33:28 -0600",
@@ -108,7 +108,7 @@
 "tests/library_checker_aizu_tests/math/partitions.test.cpp": "2025-08-28 13:19:16 -0600",
 "tests/library_checker_aizu_tests/math/prime_sieve.test.cpp": "2024-11-22 11:54:52 -0600",
 "tests/library_checker_aizu_tests/math/solve_linear_mod.test.cpp": "2026-04-12 10:51:29 -0600",
-"tests/library_checker_aizu_tests/math/tetration.test.cpp": "2024-11-17 14:04:03 -0600",
+"tests/library_checker_aizu_tests/math/tetration.test.cpp": "2026-07-06 09:26:00 -0700",
 "tests/library_checker_aizu_tests/math/totient.test.cpp": "2024-11-17 14:04:03 -0600",
 "tests/library_checker_aizu_tests/math/xor_basis_intersection.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/monotonic_stack_related/cartesian_binary_tree.test.cpp": "2026-04-06 13:24:49 -0600",
@@ -120,7 +120,7 @@
 "tests/library_checker_aizu_tests/strings/lcp_query_palindrome.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/strings/lcp_query_zfunc.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/strings/lcs_dp.test.cpp": "2025-08-05 19:19:23 -0600",
-"tests/library_checker_aizu_tests/strings/lcs_queries.test.cpp": "2026-04-06 12:17:32 -0600",
+"tests/library_checker_aizu_tests/strings/lcs_queries.test.cpp": "2026-07-06 09:26:00 -0700",
 "tests/library_checker_aizu_tests/strings/lcs_queries_merge_sort_tree.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/strings/manacher.test.cpp": "2026-04-26 11:38:07 -0600",
 "tests/library_checker_aizu_tests/strings/multi_matching_bs.test.cpp": "2026-04-26 11:38:07 -0600",
@@ -132,23 +132,23 @@
 "tests/library_checker_aizu_tests/strings/suffix_array_short.test.cpp": "2026-04-12 06:15:25 -0600",
 "tests/library_checker_aizu_tests/strings/trie.test.cpp": "2026-01-17 12:38:18 -0700",
 "tests/library_checker_aizu_tests/strings/wildcard_pattern_matching.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/trees/cd_count_paths_per_length.test.cpp": "2026-04-26 21:56:36 -0600",
-"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_query.test.cpp": "2026-04-27 08:17:20 -0600",
-"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_update.test.cpp": "2026-04-27 08:17:20 -0600",
-"tests/library_checker_aizu_tests/trees/edge_cd_count_paths_per_length.test.cpp": "2026-04-27 08:17:20 -0600",
-"tests/library_checker_aizu_tests/trees/edge_cd_reroot_dp.test.cpp": "2026-04-27 08:17:20 -0600",
-"tests/library_checker_aizu_tests/trees/hld_aizu1.test.cpp": "2026-04-12 16:21:27 -0600",
+"tests/library_checker_aizu_tests/trees/cd_count_paths_per_length.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_query.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_update.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/edge_cd_count_paths_per_length.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/edge_cd_reroot_dp.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/hld_aizu1.test.cpp": "2026-07-06 09:26:00 -0700",
 "tests/library_checker_aizu_tests/trees/hld_aizu2.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/trees/hld_lib_checker_path.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/trees/hld_lib_checker_subtree_edges.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/trees/hld_lib_checker_subtree_nodes.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/trees/kth_path_hagerup.test.cpp": "2026-06-27 13:02:40 -0500",
-"tests/library_checker_aizu_tests/trees/kth_path_ladder.test.cpp": "2026-06-27 13:02:40 -0500",
-"tests/library_checker_aizu_tests/trees/kth_path_linear.test.cpp": "2026-06-27 18:29:52 -0500",
-"tests/library_checker_aizu_tests/trees/kth_path_tree_lift.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/trees/lca_all_methods_aizu.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/trees/lca_all_methods_lib_checker.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/trees/shallowest_aizu_tree_height.test.cpp": "2026-04-12 16:21:27 -0600",
-"tests/library_checker_aizu_tests/trees/shallowest_lib_checker_tree_path_composite.test.cpp": "2026-04-26 11:38:07 -0600",
-"tests/library_checker_aizu_tests/trees/subtree_isomorphism.test.cpp": "2026-04-12 16:21:27 -0600"
+"tests/library_checker_aizu_tests/trees/hld_lib_checker_path.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/trees/hld_lib_checker_subtree_edges.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/trees/hld_lib_checker_subtree_nodes.test.cpp": "2026-07-06 09:26:00 -0700",
+"tests/library_checker_aizu_tests/trees/kth_path_hagerup.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/kth_path_ladder.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/kth_path_linear.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/kth_path_tree_lift.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/lca_all_methods_aizu.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/lca_all_methods_lib_checker.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/shallowest_aizu_tree_height.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/shallowest_lib_checker_tree_path_composite.test.cpp": "2026-07-06 09:57:36 -0700",
+"tests/library_checker_aizu_tests/trees/subtree_isomorphism.test.cpp": "2026-07-06 09:57:36 -0700"
 }

library/contest/README.md

@@ -9,7 +9,7 @@ freopen("output.txt", "w", stdout);
 If you changed something for debugging, add a `cout << "don't submit" << endl;`
 or `assert(0);` at the end of the code
 
-for policy base DS:
+for policy-based DS:
 ```
 #include <bits/extc++.h>
 ```
@@ -25,7 +25,7 @@ don't use cin for doubles/floats, it's slow, read into string, then convert to d
 cin.exceptions(cin.failbit);
 ```
 
-- use pramgas for C++ speed boost
+- use pragmas for C++ speed boost
 ```
 #pragma GCC optimize("O3,unroll-loops")
 #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

library/convolution/min_plus_convolution_convex_and_arbitrary.hpp

@@ -9,7 +9,7 @@ vi min_plus(const vi& convex, const vi& arbitrary) {
   int n = sz(convex);
   int m = sz(arbitrary);
   vi res(n + m - 1, INT_MAX);
-  auto dnc = [&](auto dnc, int res_le, int res_ri,
+  auto dnc = [&](auto&& dnc, int res_le, int res_ri,
                int arb_le, int arb_ri) {
     if (res_le >= res_ri) return;
     int mid_res = (res_le + res_ri) / 2;

library/data_structures_[l,r)/bit.hpp

@@ -7,6 +7,7 @@
 //!   int r = bit.walk2(sum);
 //!   // Returns min r s.t. sum of [0,r] >= sum
 //!   // Returns n if sum of [0,n-1] < sum
+//!   // Returns -1 if sum <= 0
 //! @endcode
 //! @time O(n + q log n)
 //! @space O(n)

library/data_structures_[l,r)/uncommon/priority_queue_of_updates.hpp

@@ -1,13 +1,12 @@
 #pragma once
 //! https://codeforces.com/blog/entry/111117
 //! @code
-//!     dsu_restorable dsu_r(n);
-//!     pq_updates<dsu_restorable, int, int> pq(dsu_r);
-//!     rep (i, 0, n) pq.ds.add(i, initial_nums[i]);
-//!     //or
-//!     pq.ds.subtree = initial_nums;
-//!     pq.push_update(u, v, cur_pri);
-//!     cout << pq.ds.sum(v) << '\n';
+//!   // DS = any struct with member functions join, undo
+//!   DS ds;
+//!   // int = argument type of DS::join
+//!   pq_updates<DS, int> pq(ds);
+//!   pq.push_update(val, pri);
+//!   pq.pop_update();
 //! @endcode
 //! @time n interweaved calls to pop_update, push_update
 //! take O(T(n)*nlogn) where O(T(n)) = time complexity of

library/data_structures_[l,r]/bit.hpp

@@ -7,6 +7,7 @@
 //!   int r = bit.walk2(sum);
 //!   // Returns min r s.t. sum of [0,r] >= sum
 //!   // Returns n if sum of [0,n-1] < sum
+//!   // Returns -1 if sum <= 0
 //! @endcode
 //! @time O(n + q log n)
 //! @space O(n)

library/graphs/bcc_callback.hpp

@@ -44,7 +44,7 @@
 void bcc(const auto& g, auto f) {
   int n = sz(g), q = 0, s = 0;
   vi t(n), st(n);
-  auto dfs = [&](auto dfs, int u) -> int {
+  auto dfs = [&](auto&& dfs, int u) -> int {
     int l = t[u] = ++q;
     for (int v : g[u]) {
       int siz = s, lu = 0;

library/graphs/euler_path.hpp

@@ -16,7 +16,7 @@
 vector<pii> euler_path(auto& g, int m, int s) {
   vi vis(m);
   vector<pii> path;
-  auto dfs = [&](auto dfs, int u, int eu) -> void {
+  auto dfs = [&](auto&& dfs, int u, int eu) -> void {
     while (!empty(g[u])) {
       auto [v, ev] = g[u].back();
       g[u].pop_back();

library/graphs/scc.hpp

@@ -11,7 +11,7 @@
 auto scc(const auto& g) {
   int n = sz(g), num_sccs = 0, q = 0, s = 0;
   vi scc_id(n, -1), tin(n), st(n);
-  auto dfs = [&](auto dfs, int u) -> int {
+  auto dfs = [&](auto&& dfs, int u) -> int {
     int low = tin[u] = ++q;
     st[s++] = u;
     for (int v : g[u])

library/graphs/strongly_connected_components/add_edges_strongly_connected.hpp

@@ -29,7 +29,7 @@ vector<pii> extra_edges(const auto& g, int num_sccs,
     zero_in[scc_id[v]] = 0;
   }
   vector<bool> vis(num_sccs);
-  auto dfs = [&](auto dfs, int u) {
+  auto dfs = [&](auto&& dfs, int u) {
     if (empty(scc_g[u])) return u;
     for (int v : scc_g[u])
       if (!vis[v]) {