Golf scc and auto param (#121)

* golf

* update bridges

* golf bridges now

* convert this now

* nits

* fix

* auto

* switch to auto

* don't use pedantic to have extra golf

* do these now

* more changes

* update

* fix

* update

* fixes

* fix

Author: lrvideckis

library/contest/random.hpp

@@ -5,11 +5,11 @@
 //!   uint64_t x1 = rng();
 //!   mt19937 rng; // fixed seed for debugging
 //!   int x2 = rnd(0, 1); //random number in [0,1]
-//!   ll x3 = rnd<ll>(1, 1e18);
+//!   ll x3 = rnd(ll(1), ll(1e18));
 //! @endcode
 mt19937 rng(
   chrono::steady_clock::now().time_since_epoch().count());
-template<class T> T rnd(T l, T r) {
+auto rnd(auto l, auto r) {
   assert(l <= r);
-  return uniform_int_distribution<T>(l, r)(rng);
+  return uniform_int_distribution(l, r)(rng);
 }

library/data_structures/dsu/range_parallel_dsu.hpp

@@ -8,16 +8,14 @@
 struct rp_dsu {
   vector<UF> ufs;
   rp_dsu(int n): ufs(bit_width(unsigned(n)), UF(n)) {}
-  template<class F>
-  void join(int l1, int l2, int len, const F& f) {
+  void join(int l1, int l2, int len, const auto& f) {
     if (len == 0) return;
     int lg = __lg(len);
     join_impl(lg, l1, l2, f);
     join_impl(lg, l1 + len - (1 << lg),
       l2 + len - (1 << lg), f);
   }
-  template<class F>
-  void join_impl(int lvl, int u, int v, const F& f) {
+  void join_impl(int lvl, int u, int v, const auto& f) {
     if (lvl == 0) {
       u = ufs[0].find(u);
       v = ufs[0].find(v);

library/data_structures/seg_tree_uncommon/find_first.hpp

@@ -25,13 +25,11 @@
 //! such element exists then `r` is returned
 //! @time O(log(n))
 //! @space O(log(n)) for recursion stack
-template<class F>
-int find_first(int l, int r, const F& f) {
+int find_first(int l, int r, const auto& f) {
   return find_first_in_range(l, r, f, 0, n, 1);
 }
 //! invariant: f(tree[v], tl, tr) is 1
-template<class F>
-int find_first_in_subtree(const F& f, int tl, int tr,
+int find_first_in_subtree(const auto& f, int tl, int tr,
   int v) {
   if (v >= n) return tl;
   int tm = split(tl, tr);
@@ -40,9 +38,8 @@ int find_first_in_subtree(const F& f, int tl, int tr,
     return find_first_in_subtree(f, tl, tm, 2 * v);
   return find_first_in_subtree(f, tm, tr, 2 * v + 1);
 }
-template<class F>
-int find_first_in_range(int l, int r, const F& f, int tl,
-  int tr, int v) {
+int find_first_in_range(int l, int r, const auto& f,
+  int tl, int tr, int v) {
   if (r <= tl || tr <= l) return r;
   if (l <= tl && tr <= r)
     return f(tree[v], tl, tr)

library/data_structures/seg_tree_uncommon/find_last.hpp

@@ -25,12 +25,11 @@
 //! such element exists then (l - 1) is returned
 //! @time O(log(n))
 //! @space O(log(n)) for recursion stack
-template<class F> int find_last(int l, int r, const F& f) {
+int find_last(int l, int r, const auto& f) {
   return find_last_in_range(l, r, f, 0, n, 1);
 }
 //! invariant: f(tree[v], tl, tr) is 1
-template<class F>
-int find_last_in_subtree(const F& f, int tl, int tr,
+int find_last_in_subtree(const auto& f, int tl, int tr,
   int v) {
   if (v >= n) return tl;
   int tm = split(tl, tr);
@@ -39,8 +38,7 @@ int find_last_in_subtree(const F& f, int tl, int tr,
     return find_last_in_subtree(f, tm, tr, 2 * v + 1);
   return find_last_in_subtree(f, tl, tm, 2 * v);
 }
-template<class F>
-int find_last_in_range(int l, int r, const F& f, int tl,
+int find_last_in_range(int l, int r, const auto& f, int tl,
   int tr, int v) {
   if (r <= tl || tr <= l) return l - 1;
   if (l <= tl && tr <= r)

library/graphs/bridges_cuts/block_vertex_tree.hpp

@@ -3,12 +3,14 @@
 //! @code
 //!   {
 //!     vector<vector<pii>> adj(n);
-//!     cuts cc(adj, m);
-//!     vector<vi> bvt = block_vertex_tree(adj, cc);
+//!     auto [num_bccs, bcc_id, is_cut] = cuts(adj, m);
+//!     vector<vi> bvt = block_vertex_tree(adj,
+//!       num_bccs, bcc_id);
 //!   }
 //!   vector<basic_string<array<int, 2>>> adj(n);
-//!   cuts cc(adj, m);
-//!   vector<vi> bvt = block_vertex_tree(adj, cc);
+//!   auto [num_bccs, bcc_id, is_cut] = cuts(adj, m);
+//!   vector<vi> bvt = block_vertex_tree(adj,
+//!     num_bccs, bcc_id);
 //!
 //!   //to loop over each unique bcc containing a node u:
 //!   for (int bccid : bvt[v]) {
@@ -21,15 +23,14 @@
 //! [n, n + num_bccs) are BCC nodes
 //! @time O(n + m)
 //! @time O(n)
-template<class G>
-vector<vi> block_vertex_tree(const G& adj,
-  const cuts<G>& cc) {
+vector<vi> block_vertex_tree(const auto& adj, int num_bccs,
+  const vi& bcc_id) {
   int n = sz(adj);
-  vector<vi> bvt(n + cc.num_bccs);
-  vector<bool> vis(cc.num_bccs);
+  vector<vi> bvt(n + num_bccs);
+  vector<bool> vis(num_bccs);
   rep(i, 0, n) {
     for (auto [_, e_id] : adj[i]) {
-      int bccid = cc.bcc_id[e_id];
+      int bccid = bcc_id[e_id];
       if (!vis[bccid]) {
         vis[bccid] = 1;
         bvt[i].push_back(bccid + n);

library/graphs/bridges_cuts/bridge_tree.hpp

@@ -3,21 +3,22 @@
 //! @code
 //!   {
 //!     vector<vector<pii>> adj(n);
-//!     bridges br(adj, m);
-//!     vector<vi> bt = bridge_tree(adj, br);
+//!     auto [num_ccs, br_id, is_br] = bridges(adj, m);
+//!     vector<vi> bt = bridge_tree(adj,
+//!       num_ccs, br_id, is_br);
 //!   }
 //!   vector<basic_string<array<int, 2>>> adj(n);
-//!   bridges br(adj, m);
-//!   vector<vi> bt = bridge_tree(adj, br);
+//!   auto [num_ccs, br_id, is_br] = bridges(adj, m);
+//!   vector<vi> bt = bridge_tree(adj,
+//!     num_ccs, br_id, is_br);
 //! @endcode
 //! @time O(n + m)
 //! @space O(n)
-template<class G>
-vector<vi> bridge_tree(const G& adj,
-  const bridges<G>& br) {
-  vector<vi> tree(br.num_ccs);
+vector<vi> bridge_tree(const auto& adj, int num_ccs,
+  const vi& br_id, const vi& is_br) {
+  vector<vi> tree(num_ccs);
   rep(i, 0, sz(adj)) for (auto [u, e_id] : adj[i]) if (
-    br.is_bridge[e_id]) tree[br.br_id[i]]
-    .push_back(br.br_id[u]);
+    is_br[e_id]) tree[br_id[i]]
+    .push_back(br_id[u]);
   return tree;
 }

library/graphs/bridges_cuts/bridges.hpp

@@ -3,7 +3,7 @@
 //! @code
 //!   {
 //!     vector<vector<pii>> adj(n);
-//!     auto [num_ccs, is_bridge, br_id] = bridges(adj, m);
+//!     auto [num_ccs, br_id, is_br] = bridges(adj, m);
 //!   }
 //!   vector<basic_string<array<int, 2>>> adj(n);
 //!   rep (i, 0, m) {
@@ -13,36 +13,29 @@
 //!     adj[u].push_back({v, i});
 //!     adj[v].push_back({u, i});
 //!   }
-//!   auto [num_ccs, is_bridge, br_id] = bridges(adj, m);
+//!   auto [num_ccs, br_id, is_br] = bridges(adj, m);
 //! @endcode
-//! is_bridge[edge id] = 1 iff bridge edge
+//! is_br[edge id] = 1 iff bridge edge
 //! br_id[v] = id, 0<=id<num_ccs
 //! @time O(n + m)
 //! @space O(n + m)
-template<class G> struct bridges {
-  int num_ccs = 0;
-  vector<bool> is_bridge;
-  vi br_id;
-  bridges(const G& adj, int m):
-    is_bridge(m), br_id(sz(adj), -1) {
-    int n = sz(adj), timer = 1;
-    vi tin(n), st;
-    auto dfs = [&](auto&& self, int v, int p_id) -> int {
-      int low = tin[v] = timer++, siz = sz(st);
-      st.push_back(v);
-      for (auto [u, e_id] : adj[v]) {
-        if (e_id == p_id) continue;
-        if (!tin[u]) low = min(low, self(self, u, e_id));
-        low = min(low, tin[u]);
-      }
-      if (tin[v] == low) {
-        if (p_id != -1) is_bridge[p_id] = 1;
-        rep(i, siz, sz(st)) br_id[st[i]] = num_ccs;
-        st.resize(siz);
-        num_ccs++;
-      }
-      return low;
-    };
-    rep(i, 0, n) if (!tin[i]) dfs(dfs, i, -1);
-  }
-};
+auto bridges(const auto& adj, int m) {
+  int n = sz(adj), num_ccs = 0, timer = 0;
+  vi br_id(n, -1), is_br(m), tin(n), st;
+  auto dfs = [&](auto&& self, int v, int p_id) -> int {
+    int low = tin[v] = ++timer, siz = sz(st);
+    st.push_back(v);
+    for (auto [u, e_id] : adj[v])
+      if (e_id != p_id && br_id[u] < 0)
+        low = min(low, tin[u] ?: self(self, u, e_id));
+    if (tin[v] == low) {
+      if (p_id != -1) is_br[p_id] = 1;
+      rep(i, siz, sz(st)) br_id[st[i]] = num_ccs;
+      st.resize(siz);
+      num_ccs++;
+    }
+    return low;
+  };
+  rep(i, 0, n) if (!tin[i]) dfs(dfs, i, -1);
+  return tuple{num_ccs, br_id, is_br};
+}

library/graphs/bridges_cuts/cuts.hpp

@@ -3,7 +3,7 @@
 //! @code
 //!   {
 //!     vector<vector<pii>> adj(n);
-//!     auto [num_bccs, is_cut, bcc_id] = cuts(adj, m);
+//!     auto [num_bccs, bcc_id, is_cut] = cuts(adj, m);
 //!   }
 //!   vector<basic_string<array<int, 2>>> adj(n);
 //!   rep (i, 0, m) {
@@ -14,45 +14,40 @@
 //!     adj[u].push_back({v, i});
 //!     adj[v].push_back({u, i});
 //!   }
-//!   auto [num_bccs, is_cut, bcc_id] = cuts(adj, m);
+//!   auto [num_bccs, bcc_id, is_cut] = cuts(adj, m);
 //! @endcode
 //! is_cut[v] = 1 iff cut node
 //! bcc_id[edge id] = id, 0<=id<num_bccs
 //! @time O(n + m)
 //! @space O(n + m)
-template<class G> struct cuts {
-  int num_bccs = 0;
-  vector<bool> is_cut;
-  vi bcc_id;
-  cuts(const G& adj, int m):
-    is_cut(sz(adj)), bcc_id(m, -1) {
-    int n = sz(adj), timer = 1;
-    vi tin(n), st;
-    auto dfs = [&](auto&& self, int v, int p_id) -> int {
-      int low = tin[v] = timer++, deg = 0;
-      for (auto [u, e_id] : adj[v]) {
-        assert(v != u);
-        if (e_id == p_id) continue;
-        if (!tin[u]) {
-          int siz = sz(st);
-          st.push_back(e_id);
-          int low_ch = self(self, u, e_id);
-          if (low_ch >= tin[v]) {
-            is_cut[v] = 1;
-            rep(i, siz, sz(st)) bcc_id[st[i]] = num_bccs;
-            st.resize(siz);
-            num_bccs++;
-          }
-          low = min(low, low_ch);
-          deg++;
-        } else if (tin[u] < tin[v]) {
-          st.push_back(e_id);
-          low = min(low, tin[u]);
+auto cuts(const auto& adj, int m) {
+  int n = sz(adj), num_bccs = 0, timer = 0;
+  vi bcc_id(m, -1), is_cut(n), tin(n), st;
+  auto dfs = [&](auto&& self, int v, int p_id) -> int {
+    int low = tin[v] = ++timer, deg = 0;
+    for (auto [u, e_id] : adj[v]) {
+      assert(v != u);
+      if (e_id == p_id) continue;
+      if (!tin[u]) {
+        int siz = sz(st);
+        st.push_back(e_id);
+        int low_ch = self(self, u, e_id);
+        if (low_ch >= tin[v]) {
+          is_cut[v] = 1;
+          rep(i, siz, sz(st)) bcc_id[st[i]] = num_bccs;
+          st.resize(siz);
+          num_bccs++;
         }
+        low = min(low, low_ch);
+        deg++;
+      } else if (tin[u] < tin[v]) {
+        st.push_back(e_id);
+        low = min(low, tin[u]);
       }
-      if (p_id == -1) is_cut[v] = (deg > 1);
-      return low;
-    };
-    rep(i, 0, n) if (!tin[i]) dfs(dfs, i, -1);
-  }
-};
+    }
+    if (p_id == -1) is_cut[v] = (deg > 1);
+    return low;
+  };
+  rep(i, 0, n) if (!tin[i]) dfs(dfs, i, -1);
+  return tuple{num_bccs, bcc_id, is_cut};
+}

library/graphs/complement_graph_ccs.hpp

@@ -13,8 +13,7 @@
 //!   cc in the compliment graph
 //! @time O(n + m)
 //! @space O(n)
-template<class G>
-vi get_complement_graph_ccs(const G& adj) {
+vi get_complement_graph_ccs(const auto& adj) {
   int n = sz(adj);
   vi cc_id(n), unseen(n);
   iota(all(unseen), 0);

library/graphs/dijkstra.hpp

@@ -10,8 +10,7 @@
 //! d[v] = min dist from source->..->v
 //! @time O(n + (m log m))
 //! @space O(n + m)
-template<class G>
-vector<ll> dijkstra(const G& adj, int s) {
+vector<ll> dijkstra(const auto& adj, int s) {
   using p = pair<ll, int>;
   priority_queue<p, vector<p>, greater<>> pq;
   pq.emplace(0, s);