feat: fn_0

src/code/tree/diam.hpp

@@ -17,8 +17,8 @@ constexpr auto tree_diam(G const& tree) {
 
   dfs(
       tree, tree.root,
-      [](u32, u32) {},
-      [](u32, u32, T const& = 1) {},
+      fn_0,
+      fn_0,
       [&](u32 to, u32 u, T const& w = 1) {
         if (T _ = mdis[to] + w; _ > mdis[u]) {
           mdis2[u] = mdis[u], midx2[u] = midx[u];
@@ -28,7 +28,7 @@ constexpr auto tree_diam(G const& tree) {
           if (midx[u] == u) midx[u] = midx[to];
         }
       },
-      [](u32, u32) {});
+      fn_0);
 
   u32 u = midx[0], v = midx2[0];
   T d = mdis[0] + mdis2[0];

src/code/tree/tree_hash_rooted.hpp

@@ -11,12 +11,12 @@ constexpr vec<u64> tree_hash_rooted(tree const &tr, Hash &&hasher) {
   vec<u64> hash(tr.g.size(), OFFSET);
   dfs(
       tr, tr.root,
-      [](u32, u32) {},
-      [](u32, u32, u32 = 1) {},
+      fn_0,
+      fn_0,
       [&](u32 to, u32 u, u32 = 1) {
         hash[u] += hasher(hash[to]);
       },
-      [](u32, u32) {});
+      fn_0);
   return hash;
 }
 

src/code/tree/tree_sumvw.hpp

@@ -10,12 +10,12 @@ constexpr vec<T> tree_sumvw(G const &tr, vec<T> const &v_weight) {
   vec<T> sumvw = v_weight;
   dfs(
       tr, tr.root,
-      [](u32, u32) {},
-      [](u32, u32, u32 = 1) {},
+      fn_0,
+      fn_0,
       [&](u32 to, u32 u, u32 = 1) {
         sumvw[u] += sumvw[to];
       },
-      [](u32, u32) {});
+      fn_0);
   return sumvw;
 }
 

src/code/util/util.hpp

@@ -61,4 +61,6 @@ constexpr u32 operator""_u32(unsigned long long x) { return (u32)x; }
 constexpr u64 operator""_u64(unsigned long long x) { return (u64)x; }
 constexpr usz operator""_uz(unsigned long long x) { return (usz)x; }
 
+inline const auto fn_0 = [](auto&&...) {};
+
 #endif

src/test_cpverifier/aizu/alds1_12_b.test.cpp

@@ -15,7 +15,7 @@ int main() {
       g.add_arc(u, v, c);
     }
   }
-  auto dis = tifa_libs::graph::dijkstra(g, 0, [](u32, u32) {});
+  auto dis = tifa_libs::graph::dijkstra(g, 0, fn_0);
   for (u32 i = 0; i < n; ++i) std::cout << i << ' ' << dis[i] << '\n';
   return 0;
 }

src/test_cpverifier/aizu/alds1_12_c.test.cpp

@@ -15,7 +15,7 @@ int main() {
       g.add_arc(u, v, c);
     }
   }
-  auto dis = tifa_libs::graph::dijkstra(g, 0, [](u32, u32) {});
+  auto dis = tifa_libs::graph::dijkstra(g, 0, fn_0);
   for (u32 i = 0; i < n; ++i) std::cout << i << ' ' << dis[i] << '\n';
   return 0;
 }

src/test_cpverifier/aizu/grl_1_a.test.cpp

@@ -13,8 +13,7 @@ int main() {
     g.add_arc(u, v, w);
   }
   constexpr u32 INF = std::numeric_limits<u32>::max() / 2 - 1;
-  auto d = tifa_libs::graph::dijkstra(
-      g, r, [](u32, u32) {}, INF);
+  auto d = tifa_libs::graph::dijkstra(g, r, fn_0, INF);
   for (u32 i : d)
     if (i == INF) std::cout << "INF\n";
     else std::cout << i << '\n';

src/test_cpverifier/aizu/grl_1_b.test.cpp

@@ -15,8 +15,7 @@ int main() {
     g.add_arc(u, v, w);
   }
   constexpr i32 INF = std::numeric_limits<i32>::max() / 2 - 1;
-  auto d = tifa_libs::graph::bellman_ford(
-      g, r, [](u32, u32) {}, INF);
+  auto d = tifa_libs::graph::bellman_ford(g, r, fn_0, INF);
   if (!d.has_value()) {
     std::cout << "NEGATIVE CYCLE\n";
     return 0;

src/test_cpverifier/library-checker/enumerate_primes.lseive.test.cpp

@@ -6,8 +6,7 @@
 int main() {
   u32 n, a, b;
   tifa_libs::fin >> n >> a >> b;
-  auto prime = tifa_libs::math::lsieve(
-      n + 1, [](u32) {}, [](u32, u32) {}, [](u32, u32) {});
+  auto prime = tifa_libs::math::lsieve(n + 1, fn_0, fn_0, fn_0);
   tifa_libs::fout << prime.size() << ' ' << (prime.size() + a - 1 - b) / a << '\n';
   for (usz i = b; i < prime.size(); i += a) tifa_libs::fout << prime[i] << " \n"[i + a >= prime.size()];
   return 0;

src/test_tinplate/util/dlx.cpp

@@ -11,7 +11,7 @@ void solve() {
       std::cin >> x;
       maps[i][j] = x;
     }
-  auto res = tifa_libs::util::DLX(maps).dance([](auto const&) {});
+  auto res = tifa_libs::util::DLX(maps).dance(fn_0);
   if (res.has_value())
     for (auto i : res.value()) std::cout << i << ' ';
   else