Edge cd modernize

.verify-helper/timestamps.remote.json

@@ -71,9 +71,9 @@
 "tests/library_checker_aizu_tests/graphs/strongly_connected_components_aizu.test.cpp": "2026-01-17 13:05:42 -0700",
 "tests/library_checker_aizu_tests/graphs/strongly_connected_components_lib_checker.test.cpp": "2026-01-17 13:05:42 -0700",
 "tests/library_checker_aizu_tests/graphs/two_edge_components.test.cpp": "2026-02-27 11:16:07 -0700",
-"tests/library_checker_aizu_tests/handmade_tests/count_paths.test.cpp": "2026-03-16 14:02:06 -0600",
+"tests/library_checker_aizu_tests/handmade_tests/count_paths.test.cpp": "2026-03-16 14:23:41 -0600",
 "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": "2026-03-16 13:39:47 -0600",
+"tests/library_checker_aizu_tests/handmade_tests/edge_cd_small_trees.test.cpp": "2026-03-16 14:23:41 -0600",
 "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": "2025-08-06 16:18:37 -0600",
 "tests/library_checker_aizu_tests/handmade_tests/hilbert_mos.test.cpp": "2026-01-18 02:20:40 +0000",
@@ -128,11 +128,11 @@
 "tests/library_checker_aizu_tests/strings/suffix_array_short.test.cpp": "2026-01-28 01:00:19 -0700",
 "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": "2025-08-05 19:19:23 -0600",
-"tests/library_checker_aizu_tests/trees/count_paths_per_length.test.cpp": "2026-03-16 13:39:47 -0600",
-"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_query.test.cpp": "2026-03-16 13:39:47 -0600",
-"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_update.test.cpp": "2026-03-16 13:39:47 -0600",
-"tests/library_checker_aizu_tests/trees/edge_cd_count_paths_per_length.test.cpp": "2026-03-16 13:39:47 -0600",
-"tests/library_checker_aizu_tests/trees/edge_cd_reroot_dp.test.cpp": "2026-03-16 13:39:47 -0600",
+"tests/library_checker_aizu_tests/trees/count_paths_per_length.test.cpp": "2026-03-16 14:13:24 -0600",
+"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_query.test.cpp": "2026-03-16 14:23:41 -0600",
+"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_update.test.cpp": "2026-03-16 14:23:41 -0600",
+"tests/library_checker_aizu_tests/trees/edge_cd_count_paths_per_length.test.cpp": "2026-03-16 14:23:41 -0600",
+"tests/library_checker_aizu_tests/trees/edge_cd_reroot_dp.test.cpp": "2026-03-16 14:23:41 -0600",
 "tests/library_checker_aizu_tests/trees/hld_aizu1.test.cpp": "2026-01-18 11:15:41 +0000",
 "tests/library_checker_aizu_tests/trees/hld_aizu2.test.cpp": "2026-01-23 04:31:29 +0000",
 "tests/library_checker_aizu_tests/trees/hld_lib_checker_path.test.cpp": "2026-01-18 11:15:41 +0000",

library/trees/edge_cd.hpp

@@ -5,47 +5,44 @@
 //! https://youtu.be/wDwaMo5xa-k
 //! @code
 //!   vector<basic_string<int>> adj(n);
-//!   edge_cd(adj, [&](const auto& adj, int cent, int m) {
+//!   edge_cd(adj, [&](int cent, int m) {
 //!     // subtrees of [0, m) of adj[cent]: 1st edge-set
 //!     // subtrees of [m, sz(adj[cent])): 2nd edge-set
 //!   });
 //! @endcode
 //! handle single-edge-paths separately
 //! @time O(n logφ n)
 //! @space O(n)
-template<class F, class G> struct edge_cd {
-  vector<G> adj;
-  F f;
-  vi siz;
-  edge_cd(const vector<G>& adj, F f):
-    adj(adj), f(f), siz(sz(adj)) {
-    dfs(0, sz(adj) - 1);
-  }
-  int find_cent(int u, int p, int m) {
+template<class G>
+void edge_cd(vector<G>& adj, const auto& f) {
+  vi siz(sz(adj));
+  auto find_cent = [&](auto&& self, int u, int p,
+                     int m) -> int {
     siz[u] = 1;
     for (int v : adj[u])
       if (v != p) {
-        int cent = find_cent(v, u, m);
+        int cent = self(self, v, u, m);
         if (cent != -1) return cent;
         siz[u] += siz[v];
       }
     return 2 * siz[u] > m
            ? p >= 0 && (siz[p] = m + 1 - siz[u]),
            u : -1;
-  }
-  void dfs(int u, int m) {
+  };
+  auto dfs = [&](auto&& self, int u, int m) -> void {
     if (m < 2) return;
-    u = find_cent(u, -1, m);
+    u = find_cent(find_cent, u, -1, m);
     int sum = 0;
     auto it = partition(all(adj[u]), [&](int v) {
       ll x = sum + siz[v];
       return x * x < m * (m - x) ? sum += siz[v], 1 : 0;
     });
-    f(adj, u, it - begin(adj[u]));
+    f(u, it - begin(adj[u]));
     G oth(it, end(adj[u]));
     adj[u].erase(it, end(adj[u]));
-    dfs(u, sum);
+    self(self, u, sum);
     swap(adj[u], oth);
-    dfs(u, m - sum);
-  }
+    self(self, u, m - sum);
+  };
+  dfs(dfs, 0, sz(adj) - 1);
 };

tests/library_checker_aizu_tests/edge_cd_asserts.hpp

@@ -1,6 +1,5 @@
 #pragma once
-void edge_cd_asserts(const vector<vi>& adj, int cent,
-  int split) {
+auto edge_cd_asserts = [&](int cent, int split) -> void {
   assert(0 < split && split < sz(adj[cent]));
   auto dfs = [&](auto&& self, int u, int p) -> int {
     int siz = 1;
@@ -47,4 +46,4 @@ void edge_cd_asserts(const vector<vi>& adj, int cent,
     assert(!is_balanced(a, cnts[0] + b));
     assert(!is_balanced(b, cnts[0] + a));
   }
-}
+};

tests/library_checker_aizu_tests/handmade_tests/count_paths.test.cpp

@@ -91,24 +91,23 @@ vector<vector<ll>> naive(const vector<vi>& adj) {
 //! @time O(n * logφ(n) * log2(n))
 //! @space this function allocates/returns various vectors
 //! which are each O(n)
-vector<ll> count_paths_per_length(const vector<vi>& adj) {
+vector<ll> count_paths_per_length(vector<vi> adj) {
   vector<ll> num_paths(sz(adj));
   if (sz(adj) >= 2) num_paths[1] = sz(adj) - 1;
-  edge_cd(adj,
-    [&](const vector<vi>& cd_adj, int cent, int split) {
-      vector<vector<double>> cnt(2, vector<double>(1));
-      auto dfs = [&](auto&& self, int u, int p, int d,
-                   int side) -> void {
-        if (sz(cnt[side]) == d) cnt[side].push_back(0.0);
-        cnt[side][d]++;
-        for (int c : cd_adj[u])
-          if (c != p) self(self, c, u, 1 + d, side);
-      };
-      rep(i, 0, sz(cd_adj[cent]))
-        dfs(dfs, cd_adj[cent][i], cent, 1, i < split);
-      vector<double> prod = conv(cnt[0], cnt[1]);
-      rep(i, 0, sz(prod)) num_paths[i] += llround(prod[i]);
-    });
+  edge_cd(adj, [&](int cent, int split) {
+    vector<vector<double>> cnt(2, vector<double>(1));
+    auto dfs = [&](auto&& self, int u, int p, int d,
+                 int side) -> void {
+      if (sz(cnt[side]) == d) cnt[side].push_back(0.0);
+      cnt[side][d]++;
+      for (int c : adj[u])
+        if (c != p) self(self, c, u, 1 + d, side);
+    };
+    rep(i, 0, sz(adj[cent]))
+      dfs(dfs, adj[cent][i], cent, 1, i < split);
+    vector<double> prod = conv(cnt[0], cnt[1]);
+    rep(i, 0, sz(prod)) num_paths[i] += llround(prod[i]);
+  });
   return num_paths;
 }
 int main() {

tests/library_checker_aizu_tests/handmade_tests/edge_cd_small_trees.test.cpp

@@ -1,23 +1,16 @@
 #define PROBLEM \
   "https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ITP1_1_A"
 #include "../template.hpp"
-#include "../edge_cd_asserts.hpp"
 #include "../../../kactl/stress-tests/utilities/genTree.h"
 #include "../../../library/trees/edge_cd.hpp"
 int main() {
   {
     vector<vector<int>> adj;
-    edge_cd(adj,
-      [&](const vector<vector<int>>&, int, int) -> void {
-        assert(false);
-      });
+    edge_cd(adj, [&](int, int) -> void { assert(false); });
   }
   {
     vector<vector<int>> adj(1);
-    edge_cd(adj,
-      [&](const vector<vector<int>>&, int, int) -> void {
-        assert(false);
-      });
+    edge_cd(adj, [&](int, int) -> void { assert(false); });
   }
   for (int n = 2; n <= 7; n++) {
     int num_codes = 1;
@@ -42,6 +35,7 @@ int main() {
         adj[u].push_back(v);
         adj[v].push_back(u);
       }
+#include "../edge_cd_asserts.hpp"
       edge_cd(adj, edge_cd_asserts);
     }
   }

tests/library_checker_aizu_tests/trees/count_paths_per_length.test.cpp

@@ -9,24 +9,23 @@
 //! @time O(n * logφ(n) * log2(n))
 //! @space this function allocates/returns various vectors
 //! which are each O(n)
-vector<ll> count_paths_per_length(const vector<vi>& adj) {
+vector<ll> count_paths_per_length(vector<vi>& adj) {
   vector<ll> num_paths(sz(adj));
   if (sz(adj) >= 2) num_paths[1] = sz(adj) - 1;
-  edge_cd(adj,
-    [&](const vector<vi>& cd_adj, int cent, int split) {
-      vector<vector<double>> cnt(2, vector<double>(1));
-      auto dfs = [&](auto&& self, int u, int p, int d,
-                   int side) -> void {
-        if (sz(cnt[side]) == d) cnt[side].push_back(0.0);
-        cnt[side][d]++;
-        for (int c : cd_adj[u])
-          if (c != p) self(self, c, u, 1 + d, side);
-      };
-      rep(i, 0, sz(cd_adj[cent]))
-        dfs(dfs, cd_adj[cent][i], cent, 1, i < split);
-      vector<double> prod = conv(cnt[0], cnt[1]);
-      rep(i, 0, sz(prod)) num_paths[i] += llround(prod[i]);
-    });
+  edge_cd(adj, [&](int cent, int split) {
+    vector<vector<double>> cnt(2, vector<double>(1));
+    auto dfs = [&](auto&& self, int u, int p, int d,
+                 int side) -> void {
+      if (sz(cnt[side]) == d) cnt[side].push_back(0.0);
+      cnt[side][d]++;
+      for (int c : adj[u])
+        if (c != p) self(self, c, u, 1 + d, side);
+    };
+    rep(i, 0, sz(adj[cent]))
+      dfs(dfs, adj[cent][i], cent, 1, i < split);
+    vector<double> prod = conv(cnt[0], cnt[1]);
+    rep(i, 0, sz(prod)) num_paths[i] += llround(prod[i]);
+  });
   return num_paths;
 }
 int main() {

tests/library_checker_aizu_tests/trees/edge_cd_contour_range_query.test.cpp

@@ -1,7 +1,6 @@
 #define PROBLEM \
   "https://judge.yosupo.jp/problem/vertex_add_range_contour_sum_on_tree"
 #include "../template.hpp"
-#include "../edge_cd_asserts.hpp"
 #include "../../../library/data_structures_[l,r)/bit.hpp"
 #include "../../../library/trees/edge_cd.hpp"
 struct sum_adj {
@@ -47,25 +46,23 @@ struct contour_range_query {
   //! @param a a[u] = initial number for node u
   //! @time O(n logφ n)
   //! @space O(n logφ n) for `info` and `bits`
-  contour_range_query(const vector<vi>& adj,
-    const vector<ll>& a):
+  contour_range_query(vector<vi> adj, const vector<ll>& a):
     n(sz(a)), sum_a(adj, a), info(n) {
-    edge_cd(adj,
-      [&](const vector<vi>& cd_adj, int cent, int split) {
-        vector<vector<ll>> sum_num(2, vector<ll>(1));
-        auto dfs = [&](auto&& self, int u, int p, int d,
-                     int side) -> void {
-          info[u].push_back({int(sz(bits)), d, side});
-          if (sz(sum_num[side]) == d)
-            sum_num[side].push_back(0);
-          sum_num[side][d] += a[u];
-          for (int c : cd_adj[u])
-            if (c != p) self(self, c, u, 1 + d, side);
-        };
-        rep(i, 0, sz(cd_adj[cent]))
-          dfs(dfs, cd_adj[cent][i], cent, 1, i < split);
-        bits.push_back({BIT(sum_num[0]), BIT(sum_num[1])});
-      });
+    edge_cd(adj, [&](int cent, int split) {
+      vector<vector<ll>> sum_num(2, vector<ll>(1));
+      auto dfs = [&](auto&& self, int u, int p, int d,
+                   int side) -> void {
+        info[u].push_back({int(sz(bits)), d, side});
+        if (sz(sum_num[side]) == d)
+          sum_num[side].push_back(0);
+        sum_num[side][d] += a[u];
+        for (int c : adj[u])
+          if (c != p) self(self, c, u, 1 + d, side);
+      };
+      rep(i, 0, sz(adj[cent]))
+        dfs(dfs, adj[cent][i], cent, 1, i < split);
+      bits.push_back({BIT(sum_num[0]), BIT(sum_num[1])});
+    });
   }
   //! @param u node
   //! @param delta number to add to node u's number
@@ -108,8 +105,11 @@ int main() {
     adj[u].push_back(v);
     adj[v].push_back(u);
   }
-  { edge_cd(adj, edge_cd_asserts); }
   contour_range_query cq(adj, a);
+  {
+#include "../edge_cd_asserts.hpp"
+    edge_cd(adj, edge_cd_asserts);
+  }
   while (q--) {
     int type;
     cin >> type;

tests/library_checker_aizu_tests/trees/edge_cd_contour_range_update.test.cpp

@@ -1,7 +1,6 @@
 #define PROBLEM \
   "https://judge.yosupo.jp/problem/vertex_get_range_contour_add_on_tree"
 #include "../template.hpp"
-#include "../edge_cd_asserts.hpp"
 #include "../../../library/data_structures_[l,r)/bit_uncommon/rupq.hpp"
 #include "../../../library/trees/edge_cd.hpp"
 struct sum_adj {
@@ -49,24 +48,23 @@ struct contour_range_update {
   //! @param a a[u] = initial number for node u
   //! @time O(n logφ n)
   //! @space O(n logφ n) for `info` and `bits`
-  contour_range_update(const vector<vi>& adj,
+  contour_range_update(vector<vi> adj,
     const vector<ll>& a):
     n(sz(a)), a(a), sum_a(adj, vector<ll>(n)), info(n) {
-    edge_cd(adj,
-      [&](const vector<vi>& cd_adj, int cent, int split) {
-        array<int, 2> mx_d = {0, 0};
-        auto dfs = [&](auto&& self, int u, int p, int d,
-                     int side) -> void {
-          mx_d[side] = max(mx_d[side], d);
-          info[u].push_back({int(sz(bits)), d, side});
-          for (int v : cd_adj[u])
-            if (v != p) self(self, v, u, 1 + d, side);
-        };
-        rep(i, 0, sz(cd_adj[cent]))
-          dfs(dfs, cd_adj[cent][i], cent, 1, i < split);
-        bits.push_back(
-          {bit_rupq(mx_d[0] + 1), bit_rupq(mx_d[1] + 1)});
-      });
+    edge_cd(adj, [&](int cent, int split) {
+      array<int, 2> mx_d = {0, 0};
+      auto dfs = [&](auto&& self, int u, int p, int d,
+                   int side) -> void {
+        mx_d[side] = max(mx_d[side], d);
+        info[u].push_back({int(sz(bits)), d, side});
+        for (int v : adj[u])
+          if (v != p) self(self, v, u, 1 + d, side);
+      };
+      rep(i, 0, sz(adj[cent]))
+        dfs(dfs, adj[cent][i], cent, 1, i < split);
+      bits.push_back(
+        {bit_rupq(mx_d[0] + 1), bit_rupq(mx_d[1] + 1)});
+    });
   }
   //! @param u,l,r,delta add delta to all nodes v such
   //! that l <= dist(u, v) < r
@@ -106,8 +104,11 @@ int main() {
     adj[u].push_back(v);
     adj[v].push_back(u);
   }
-  { edge_cd(adj, edge_cd_asserts); }
   contour_range_update cu(adj, a);
+  {
+#include "../edge_cd_asserts.hpp"
+    edge_cd(adj, edge_cd_asserts);
+  }
   while (q--) {
     int type;
     cin >> type;