Merge remote-tracking branch 'origin/dev' into cpp20

# Conflicts:
#	.verify-helper/timestamps.remote.json
#	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": "2026-07-06 10:14:01 -0700",
 "tests/library_checker_aizu_tests/data_structures/deque_index.test.cpp": "2026-07-06 10:14:01 -0700",
 "tests/library_checker_aizu_tests/data_structures/deque_op.test.cpp": "2026-07-06 10:14:01 -0700",
@@ -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": "2026-07-06 09:32:13 -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/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 10:14:01 -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": "2026-07-06 09:32:13 -0700",
-"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": "2026-07-06 10:14:01 -0700",
-"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": "2026-07-06 09:32:13 -0700",
 "tests/library_checker_aizu_tests/strings/lcp_query_zfunc.test.cpp": "2026-07-06 09:32:13 -0700",
 "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": "2026-07-06 09:32:13 -0700",
@@ -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": "2026-07-06 09:32:13 -0700",
-"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/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 10:14:01 -0700",
-"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_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 10:14:01 -0700",
 "tests/library_checker_aizu_tests/trees/lca_all_methods_aizu.test.cpp": "2026-07-06 10:14:01 -0700",
 "tests/library_checker_aizu_tests/trees/lca_all_methods_lib_checker.test.cpp": "2026-07-06 10:14:01 -0700",
-"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/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)
@@ -19,9 +20,9 @@ struct BIT {
     for (; i < sz(s); i |= i + 1) s[i] += d;
   }
   ll query(int r) {
-    ll ret = 0;
-    for (; r > 0; r &= r - 1) ret += s[r - 1];
-    return ret;
+    ll res = 0;
+    for (; r > 0; r &= r - 1) res += s[r - 1];
+    return res;
   }
   ll query(int l, int r) { return query(r) - query(l); }
 #include "bit_uncommon/walk_lambda.hpp"

library/data_structures_[l,r)/bit_uncommon/kd_bit.hpp

@@ -19,10 +19,10 @@ template<int K> struct KD_BIT {
     for (; i < sz(s); i |= i + 1) s[i].update(a...);
   }
   ll query(int l, int r, auto... a) {
-    ll ans = 0;
-    for (; l < r; r &= r - 1) ans += s[r - 1].query(a...);
-    for (; r < l; l &= l - 1) ans -= s[l - 1].query(a...);
-    return ans;
+    ll res = 0;
+    for (; l < r; r &= r - 1) res += s[r - 1].query(a...);
+    for (; r < l; l &= l - 1) res -= s[l - 1].query(a...);
+    return res;
   }
 };
 template<> struct KD_BIT<0> {

library/data_structures_[l,r)/seg_tree_uncommon/kth_smallest_query.hpp

@@ -26,12 +26,12 @@ struct kth_smallest {
   int query(int k, int tl, int tr, int vl, int vr) {
     if (tr - tl == 1) return tl;
     int tm = tl + (tr - tl) / 2;
-    int left_count = pst.tree[pst.tree[vr].lch].sum -
-                     pst.tree[pst.tree[vl].lch].sum;
-    if (left_count >= k)
+    int cnt_l = pst.tree[pst.tree[vr].lch].sum -
+                pst.tree[pst.tree[vl].lch].sum;
+    if (cnt_l >= k)
       return query(k, tl, tm, pst.tree[vl].lch,
         pst.tree[vr].lch);
-    return query(k - left_count, tm, tr, pst.tree[vl].rch,
+    return query(k - cnt_l, tm, tr, pst.tree[vl].rch,
       pst.tree[vr].rch);
   }
 };

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

@@ -24,9 +24,9 @@ template<class T, class F> struct deq {
   T front() { return (empty(l) ? r[0] : l.back())[0]; }
   T back() { return (empty(r) ? l[0] : r.back())[0]; }
   int siz() { return sz(l) + sz(r); }
-  void push_back(T elem) {
+  void push_back(T val) {
     r.push_back(
-      {elem, empty(r) ? elem : op(r.back()[1], elem)});
+      {val, empty(r) ? val : op(r.back()[1], val)});
   }
   void pop_back() {
     if (empty(r)) {
@@ -37,9 +37,9 @@ template<class T, class F> struct deq {
     }
     r.pop_back();
   }
-  void push_front(T elem) {
+  void push_front(T val) {
     l.push_back(
-      {elem, empty(l) ? elem : op(elem, l.back()[1])});
+      {val, empty(l) ? val : op(val, l.back()[1])});
   }
   void pop_front() {
     if (empty(l)) {

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

@@ -3,20 +3,20 @@ const int b = 318; //!< sqrt(1e5)
 //! https://noshi91.hatenablog.com/entry/2020/10/26/140105
 struct mode_query {
   int n;
-  vi a, cnt, index_into_index;
-  vector<vi> index;
+  vi a, cnt, pos_idx;
+  vector<vi> pos;
   vector<vector<pii>>
     mode_blocks; //!< {mode, cnt} of range of blocks
   //! @param a compressed array: 0 <= a[i] < n
   //! @time O(n * sqrt(n))
   //! @space O(n)
   mode_query(const vi& a):
-    n(sz(a)), a(a), cnt(n), index_into_index(n), index(n),
+    n(sz(a)), a(a), cnt(n), pos_idx(n), pos(n),
     mode_blocks((n + b - 1) / b,
       vector<pii>((n + b - 1) / b)) {
     rep(i, 0, n) {
-      index_into_index[i] = sz(index[a[i]]);
-      index[a[i]].push_back(i);
+      pos_idx[i] = sz(pos[a[i]]);
+      pos[a[i]].push_back(i);
     }
     for (int start = 0; start < n; start += b) {
       int mode = a[start];
@@ -51,17 +51,17 @@ struct mode_query {
     for (int i = l / b * b + b - 1; i >= l; i--)
       cnt[a[i]]++;
     for (int i = l / b * b + b - 1; i >= l; i--) {
-      int idx = index_into_index[i];
-      if (idx + res.second < sz(index[a[i]]) &&
-          index[a[i]][idx + res.second] < r)
+      int idx = pos_idx[i];
+      if (idx + res.second < sz(pos[a[i]]) &&
+          pos[a[i]][idx + res.second] < r)
         res = {a[i], cnt[a[i]] + res.second};
       cnt[a[i]]--;
     }
     rep(i, (r - 1) / b * b, r) cnt[a[i]]++;
     rep(i, (r - 1) / b * b, r) {
-      int idx = index_into_index[i];
+      int idx = pos_idx[i];
       if (idx >= res.second &&
-          index[a[i]][idx - res.second] >= l)
+          pos[a[i]][idx - res.second] >= l)
         res = {a[i], cnt[a[i]] + res.second};
       cnt[a[i]]--;
     }