diff --git a/library/graphs/bcc_callback.hpp b/library/graphs/bcc_callback.hpp
index f751b908..0d74de3c 100644
--- a/library/graphs/bcc_callback.hpp
+++ b/library/graphs/bcc_callback.hpp
@@ -9,8 +9,8 @@
 //!       int count_edges = 0;
 //!       rep (i, 0, sz(nodes) - 1) {
 //!         seen[nodes[i]] = 1;
-//!         for (int v : adj[nodes[i]]) if (!seen[v]) {
-//!           // edge nodes[i] <=> v is in current BCC
+//!         for (int u : adj[nodes[i]]) if (!seen[u]) {
+//!           // edge nodes[i] <=> u is in current BCC
 //!           count_edges++;
 //!         }
 //!       }
@@ -18,22 +18,22 @@
 //!         // nodes[0] <=> nodes[1] is a bridge
 //!         return;
 //!       }
-//!       for (int v : nodes) uf.join(v, nodes[0]);
+//!       for (int u : nodes) uf.join(u, nodes[0]);
 //!     });
 //!     vector<basic_string<int>> bridge_tree(n);
 //!     rep (i, 0, n)
-//!       for (int v : adj[i])
-//!         if (!uf.sameSet(i, v))
-//!           bridge_tree[uf.find(i)] += uf.find(v);
+//!       for (int u : adj[i])
+//!         if (!uf.sameSet(i, u))
+//!           bridge_tree[uf.find(i)] += uf.find(u);
 //!   }
 //!
 //!   vector<basic_string<int>> adj(n);
 //!   vector<basic_string<int>> block_vertex_tree(2 * n);
 //!   int bcc_id = n;
 //!   bcc_callback(adj, [&](const vi& nodes) {
-//!     for (int v : nodes) {
-//!       block_vertex_tree[v] += bcc_id;
-//!       block_vertex_tree[bcc_id] += v;
+//!     for (int u : nodes) {
+//!       block_vertex_tree[u] += bcc_id;
+//!       block_vertex_tree[bcc_id] += u;
 //!     }
 //!     bcc_id++;
 //!   });
@@ -44,13 +44,13 @@
 void bcc_callback(const auto& adj, auto f) {
   int n = sz(adj), q = 0, s = 0;
   vi t(n), st(n);
-  auto dfs = [&](auto&& self, int v) -> int {
-    int l = t[v] = ++q;
-    for (int u : adj[v]) {
+  auto dfs = [&](auto&& self, int u) -> int {
+    int l = t[u] = ++q;
+    for (int v : adj[u]) {
       int siz = s, lu = 0;
-      l = min(l, t[u] ?: (lu = self(self, st[s++] = u)));
-      if (lu >= t[v]) {
-        st[s++] = v;
+      l = min(l, t[v] ?: (lu = self(self, st[s++] = v)));
+      if (lu >= t[u]) {
+        st[s++] = u;
         f({siz + all(st) - n + s});
         s = siz;
       }
diff --git a/library/graphs/hopcroft_karp.hpp b/library/graphs/hopcroft_karp.hpp
index 9d504347..bef7262f 100644
--- a/library/graphs/hopcroft_karp.hpp
+++ b/library/graphs/hopcroft_karp.hpp
@@ -29,31 +29,31 @@ struct hopcroft_karp {
       mvc_l.assign(lsz, 1);
       mvc_r.assign(rsz, 0);
       while (!empty(q)) {
-        int v = q.front();
+        int u = q.front();
         q.pop();
-        mvc_l[v] = 0;
-        for (int u : adj[v]) {
-          mvc_r[u] = 1;
-          int w = to_l[u];
+        mvc_l[u] = 0;
+        for (int v : adj[u]) {
+          mvc_r[v] = 1;
+          int w = to_l[v];
           if (w == -1) found = 1;
           else if (level[w] == -1) {
-            level[w] = level[v] + 1;
+            level[w] = level[u] + 1;
             q.push(w);
           }
         }
       }
       if (!found) break;
-      auto dfs = [&](auto&& self, int v) -> bool {
-        for (int u : adj[v]) {
-          int w = to_l[u];
+      auto dfs = [&](auto&& self, int u) -> bool {
+        for (int v : adj[u]) {
+          int w = to_l[v];
           if (w == -1 ||
-            (level[v] + 1 == level[w] && self(self, w))) {
-            to_r[v] = u;
-            to_l[u] = v;
+            (level[u] + 1 == level[w] && self(self, w))) {
+            to_r[u] = v;
+            to_l[v] = u;
             return 1;
           }
         }
-        level[v] = INT_MAX;
+        level[u] = INT_MAX;
         return 0;
       };
       rep(i, 0, lsz) m_sz +=
diff --git a/library/graphs/scc.hpp b/library/graphs/scc.hpp
index 4691e704..c585a81e 100644
--- a/library/graphs/scc.hpp
+++ b/library/graphs/scc.hpp
@@ -4,21 +4,21 @@
 //!   vector<basic_string<int>> adj(n);
 //!   auto [num_sccs, scc_id] = sccs(adj);
 //! @endcode
-//! scc_id[v] = id, 0<=id<num_sccs
+//! scc_id[u] = id, 0<=id<num_sccs
 //! for each edge u -> v: scc_id[u] >= scc_id[v]
 //! @time O(n + m)
 //! @space O(n)
 auto sccs(const auto& adj) {
   int n = sz(adj), num_sccs = 0, q = 0, s = 0;
   vi scc_id(n, -1), tin(n), st(n);
-  auto dfs = [&](auto&& self, int v) -> int {
-    int low = tin[v] = ++q;
-    st[s++] = v;
-    for (int u : adj[v])
-      if (scc_id[u] < 0)
-        low = min(low, tin[u] ?: self(self, u));
-    if (tin[v] == low) {
-      while (scc_id[v] < 0) scc_id[st[--s]] = num_sccs;
+  auto dfs = [&](auto&& self, int u) -> int {
+    int low = tin[u] = ++q;
+    st[s++] = u;
+    for (int v : adj[u])
+      if (scc_id[v] < 0)
+        low = min(low, tin[v] ?: self(self, v));
+    if (tin[u] == low) {
+      while (scc_id[u] < 0) scc_id[st[--s]] = num_sccs;
       num_sccs++;
     }
     return low;
diff --git a/library/graphs/strongly_connected_components/add_edges_strongly_connected.hpp b/library/graphs/strongly_connected_components/add_edges_strongly_connected.hpp
index c4d56556..0bf5897c 100644
--- a/library/graphs/strongly_connected_components/add_edges_strongly_connected.hpp
+++ b/library/graphs/strongly_connected_components/add_edges_strongly_connected.hpp
@@ -23,18 +23,18 @@ vector<pii> extra_edges(const auto& adj, int num_sccs,
   int n = sz(adj);
   vector<vi> scc_adj(num_sccs);
   vector<bool> zero_in(num_sccs, 1);
-  rep(i, 0, n) for (int u : adj[i]) {
-    if (scc_id[i] == scc_id[u]) continue;
-    scc_adj[scc_id[i]].push_back(scc_id[u]);
-    zero_in[scc_id[u]] = 0;
+  rep(i, 0, n) for (int v : adj[i]) {
+    if (scc_id[i] == scc_id[v]) continue;
+    scc_adj[scc_id[i]].push_back(scc_id[v]);
+    zero_in[scc_id[v]] = 0;
   }
   vector<bool> vis(num_sccs);
-  auto dfs = [&](auto&& self, int v) {
-    if (empty(scc_adj[v])) return v;
-    for (int u : scc_adj[v])
-      if (!vis[u]) {
-        vis[u] = 1;
-        int zero_out = self(self, u);
+  auto dfs = [&](auto&& self, int u) {
+    if (empty(scc_adj[u])) return u;
+    for (int v : scc_adj[u])
+      if (!vis[v]) {
+        vis[v] = 1;
+        int zero_out = self(self, v);
         if (zero_out != -1) return zero_out;
       }
     return -1;
@@ -55,7 +55,7 @@ vector<pii> extra_edges(const auto& adj, int num_sccs,
       in_unused.pop_back();
     } else edges.emplace_back(i, num_sccs - 1);
   }
-  for (int v : in_unused) edges.emplace_back(0, v);
+  for (int u : in_unused) edges.emplace_back(0, u);
   vi to_node(num_sccs);
   rep(i, 0, n) to_node[scc_id[i]] = i;
   for (auto& [u, v] : edges)
diff --git a/library/graphs/uncommon/bridges.hpp b/library/graphs/uncommon/bridges.hpp
index 5b2ddcb5..b7ab1cc2 100644
--- a/library/graphs/uncommon/bridges.hpp
+++ b/library/graphs/uncommon/bridges.hpp
@@ -18,15 +18,15 @@
 auto bridges(const auto& adj, int m) {
   int n = sz(adj), num_ccs = 0, q = 0, s = 0;
   vi br_id(n, -1), is_br(m), tin(n), st(n);
-  auto dfs = [&](auto&& self, int v, int p) -> int {
-    int low = tin[v] = ++q;
-    st[s++] = v;
-    for (auto [u, e] : adj[v])
-      if (e != p && br_id[u] < 0)
-        low = min(low, tin[u] ?: self(self, u, e));
-    if (tin[v] == low) {
+  auto dfs = [&](auto&& self, int u, int p) -> int {
+    int low = tin[u] = ++q;
+    st[s++] = u;
+    for (auto [v, e] : adj[u])
+      if (e != p && br_id[v] < 0)
+        low = min(low, tin[v] ?: self(self, v, e));
+    if (tin[u] == low) {
       if (p != -1) is_br[p] = 1;
-      while (br_id[v] < 0) br_id[st[--s]] = num_ccs;
+      while (br_id[u] < 0) br_id[st[--s]] = num_ccs;
       num_ccs++;
     }
     return low;
diff --git a/library/graphs/uncommon/cuts.hpp b/library/graphs/uncommon/cuts.hpp
index 1f7068a0..103c19a5 100644
--- a/library/graphs/uncommon/cuts.hpp
+++ b/library/graphs/uncommon/cuts.hpp
@@ -19,16 +19,16 @@
 auto cuts(const auto& adj, int m) {
   int n = sz(adj), num_bccs = 0, q = 0, s = 0;
   vi bcc_id(m, -1), is_cut(n), tin(n), st(m);
-  auto dfs = [&](auto&& self, int v, int p) -> int {
-    int low = tin[v] = ++q;
-    for (auto [u, e] : adj[v]) {
-      assert(v != u);
+  auto dfs = [&](auto&& self, int u, int p) -> int {
+    int low = tin[u] = ++q;
+    for (auto [v, e] : adj[u]) {
+      assert(u != v);
       if (e == p) continue;
-      if (tin[u] < tin[v]) st[s++] = e;
+      if (tin[v] < tin[u]) st[s++] = e;
       int lu = -1;
-      low = min(low, tin[u] ?: (lu = self(self, u, e)));
-      if (lu >= tin[v]) {
-        is_cut[v] = p >= 0 || tin[v] + 1 < tin[u];
+      low = min(low, tin[v] ?: (lu = self(self, v, e)));
+      if (lu >= tin[u]) {
+        is_cut[u] = p >= 0 || tin[u] + 1 < tin[v];
         while (bcc_id[e] < 0) bcc_id[st[--s]] = num_bccs;
         num_bccs++;
       }
diff --git a/library/trees/hld.hpp b/library/trees/hld.hpp
index aaae48b6..50524362 100644
--- a/library/trees/hld.hpp
+++ b/library/trees/hld.hpp
@@ -5,7 +5,7 @@
 //!   HLD<0> hld(adj);
 //!   hld.path(u, v, [&](int l, int r) { // [l, r)
 //!   });
-//!   auto [l, r] = hld.subtree(v); // [l, r)
+//!   auto [l, r] = hld.subtree(u); // [l, r)
 //! @endcode
 //! @time O(n + q log^2 n)
 //! @space O(n)
@@ -15,23 +15,23 @@ template<bool VALS_EDGES> struct HLD {
   vi p, siz, rt, tin;
   HLD(auto& adj):
     n(sz(adj)), p(n), siz(n, 1), rt(n), tin(n) {
-    auto dfs1 = [&](auto&& self, int v) -> void {
-      for (int& u : adj[v]) {
-        iter_swap(ranges::find(adj[u], v), rbegin(adj[u]));
-        adj[u].pop_back();
-        p[u] = v;
-        self(self, u);
-        siz[v] += siz[u];
-        if (siz[u] > siz[adj[v][0]]) swap(u, adj[v][0]);
+    auto dfs1 = [&](auto&& self, int u) -> void {
+      for (int& v : adj[u]) {
+        iter_swap(ranges::find(adj[v], u), rbegin(adj[v]));
+        adj[v].pop_back();
+        p[v] = u;
+        self(self, v);
+        siz[u] += siz[v];
+        if (siz[v] > siz[adj[u][0]]) swap(v, adj[u][0]);
       }
     };
     dfs1(dfs1, 0);
     int tim = 0;
-    auto dfs2 = [&](auto&& self, int v) -> void {
-      tin[v] = tim++;
-      for (int u : adj[v]) {
-        rt[u] = (u == adj[v][0] ? rt[v] : u);
-        self(self, u);
+    auto dfs2 = [&](auto&& self, int u) -> void {
+      tin[u] = tim++;
+      for (int v : adj[u]) {
+        rt[v] = (v == adj[u][0] ? rt[u] : v);
+        self(self, v);
       }
     };
     dfs2(dfs2, 0);
@@ -44,7 +44,7 @@ template<bool VALS_EDGES> struct HLD {
     }
     f(tin[u] + VALS_EDGES, tin[v] + 1);
   }
-  pii subtree(int v) {
-    return {tin[v] + VALS_EDGES, tin[v] + siz[v]};
+  pii subtree(int u) {
+    return {tin[u] + VALS_EDGES, tin[u] + siz[u]};
   }
 };
diff --git a/library/trees/lca_rmq.hpp b/library/trees/lca_rmq.hpp
index 5db4bd4b..9a2c325b 100644
--- a/library/trees/lca_rmq.hpp
+++ b/library/trees/lca_rmq.hpp
@@ -16,12 +16,12 @@ struct LCA {
   LCA(const auto& adj):
     n(sz(adj)), tin(n), siz(n, 1), d(n), p(n) {
     vi order;
-    auto dfs = [&](auto&& self, int v) -> void {
-      tin[v] = sz(order), order.push_back(v);
-      for (int u : adj[v])
-        if (u != p[v])
-          d[u] = d[p[u] = v] + 1, self(self, u),
-          siz[v] += siz[u];
+    auto dfs = [&](auto&& self, int u) -> void {
+      tin[u] = sz(order), order.push_back(u);
+      for (int v : adj[u])
+        if (v != p[u])
+          d[v] = d[p[v] = u] + 1, self(self, v),
+          siz[u] += siz[v];
     };
     dfs(dfs, 0);
     rmq = {order,
diff --git a/library/trees/linear_kth_par.hpp b/library/trees/linear_kth_par.hpp
index 267fc998..e2254892 100644
--- a/library/trees/linear_kth_par.hpp
+++ b/library/trees/linear_kth_par.hpp
@@ -21,28 +21,28 @@ template<int KAPPA = 2> struct linear_kth_par {
       jmp[t] = st[max(0, s - KAPPA * (t & -t))];
       t++;
     };
-    auto dfs = [&](auto&& self, int v, int p) -> void {
-      int& l = leaf[v] = st[d[v]] = v;
-      pos[v] = t;
-      calc(d[v]);
-      for (int u : adj[v])
-        if (u != p) {
-          d[u] = 1 + d[v];
-          self(self, u, v);
-          if (d[l] < d[leaf[u]]) l = leaf[u];
-          calc(d[v]);
+    auto dfs = [&](auto&& self, int u, int p) -> void {
+      int& l = leaf[u] = st[d[u]] = u;
+      pos[u] = t;
+      calc(d[u]);
+      for (int v : adj[u])
+        if (v != p) {
+          d[v] = 1 + d[u];
+          self(self, v, u);
+          if (d[l] < d[leaf[v]]) l = leaf[v];
+          calc(d[u]);
         }
-      int s = (d[l] - d[v]) * (2 * KAPPA + 3) / KAPPA;
+      int s = (d[l] - d[u]) * (2 * KAPPA + 3) / KAPPA;
       s = min(max(s, 2 * KAPPA), d[l] + 1);
       rep(i, sz(lad[l]), s) lad[l].push_back(st[d[l] - i]);
     };
     dfs(dfs, 0, 0);
   }
-  int kth_par(int v, int k) {
-    assert(0 <= k && k <= d[v]);
-    int anc_d = d[v] - k;
+  int kth_par(int u, int k) {
+    assert(0 <= k && k <= d[u]);
+    int anc_d = d[u] - k;
     if (unsigned j = k / (KAPPA + 1); j)
-      j = bit_floor(j), v = jmp[(pos[v] & -j) | j];
-    return v = leaf[v], lad[v][d[v] - anc_d];
+      j = bit_floor(j), u = jmp[(pos[u] & -j) | j];
+    return u = leaf[u], lad[u][d[u] - anc_d];
   }
 };
diff --git a/library/trees/linear_lca.hpp b/library/trees/linear_lca.hpp
index d315c641..49fad5c2 100644
--- a/library/trees/linear_lca.hpp
+++ b/library/trees/linear_lca.hpp
@@ -13,19 +13,19 @@ struct linear_lca {
   linear_lca(const auto& adj):
     n(sz(adj)), d(n), in(n), asc(n), head(n + 1) {
     vector<pii> order;
-    auto dfs = [&](auto&& self, int v, int p) -> void {
-      order.emplace_back(v, p);
-      in[v] = sz(order);
-      for (int u : adj[v])
-        if (u != p) {
-          d[u] = 1 + d[v];
-          self(self, u, v);
-          head[in[u]] = v;
-          if (lsb(in[v]) < lsb(in[u])) in[v] = in[u];
+    auto dfs = [&](auto&& self, int u, int p) -> void {
+      order.emplace_back(u, p);
+      in[u] = sz(order);
+      for (int v : adj[u])
+        if (v != p) {
+          d[v] = 1 + d[u];
+          self(self, v, u);
+          head[in[v]] = u;
+          if (lsb(in[u]) < lsb(in[v])) in[u] = in[v];
         }
     };
     dfs(dfs, 0, 0);
-    for (auto [v, p] : order) asc[v] = asc[p] | lsb(in[v]);
+    for (auto [u, p] : order) asc[u] = asc[p] | lsb(in[u]);
   }
   int lca(int u, int v) {
     if (unsigned j = in[u] ^ in[v]; j) {
diff --git a/library/trees/shallowest_decomp_tree.hpp b/library/trees/shallowest_decomp_tree.hpp
index 8256982c..c9e0ceab 100644
--- a/library/trees/shallowest_decomp_tree.hpp
+++ b/library/trees/shallowest_decomp_tree.hpp
@@ -9,23 +9,23 @@
 //! @space O(n)
 void shallowest(auto& adj, auto f) {
   vector<vi> order(bit_width(size(adj)));
-  auto dfs = [&](auto&& self, int v, int p) -> int {
+  auto dfs = [&](auto&& self, int u, int p) -> int {
     int once = 0, twice = 0;
-    for (int u : adj[v])
-      if (u != p) {
-        int dp = self(self, u, v);
+    for (int v : adj[u])
+      if (v != p) {
+        int dp = self(self, v, u);
         twice |= once & dp, once |= dp;
       }
     auto dp = (once | (bit_ceil(twice + 1u) - 1)) + 1;
-    order[countr_zero(dp)].push_back(v);
+    order[countr_zero(dp)].push_back(u);
     return dp;
   };
   dfs(dfs, 0, 0);
   for (const vi& vec : order | views::reverse)
-    for (int v : vec) {
-      f(v);
-      for (int u : adj[v])
-        iter_swap(ranges::find(adj[u], v), rbegin(adj[u])),
-          adj[u].pop_back();
+    for (int u : vec) {
+      f(u);
+      for (int v : adj[u])
+        iter_swap(ranges::find(adj[v], u), rbegin(adj[v])),
+          adj[v].pop_back();
     }
 }
diff --git a/library/trees/tree_lift.hpp b/library/trees/tree_lift.hpp
index 3a6e574b..08e1e00a 100644
--- a/library/trees/tree_lift.hpp
+++ b/library/trees/tree_lift.hpp
@@ -11,20 +11,20 @@
 struct tree_lift {
   vi d, p, j;
   tree_lift(const auto& adj): d(sz(adj)), p(d), j(d) {
-    auto dfs = [&](auto&& self, int v) -> void {
+    auto dfs = [&](auto&& self, int u) -> void {
       int up =
-        d[v] + d[j[j[v]]] == 2 * d[j[v]] ? j[j[v]] : v;
-      for (int u : adj[v])
-        if (u != p[v])
-          d[u] = d[p[u] = v] + 1, j[u] = up, self(self, u);
+        d[u] + d[j[j[u]]] == 2 * d[j[u]] ? j[j[u]] : u;
+      for (int v : adj[u])
+        if (v != p[u])
+          d[v] = d[p[v] = u] + 1, j[v] = up, self(self, v);
     };
     dfs(dfs, 0);
   }
-  int kth_par(int v, int k) {
-    int anc_d = d[v] - k;
-    while (d[v] > anc_d)
-      v = d[j[v]] >= anc_d ? j[v] : p[v];
-    return v;
+  int kth_par(int u, int k) {
+    int anc_d = d[u] - k;
+    while (d[u] > anc_d)
+      u = d[j[u]] >= anc_d ? j[u] : p[u];
+    return u;
   }
   int lca(int u, int v) {
     if (d[u] < d[v]) swap(u, v);
diff --git a/library/trees/uncommon/contour_range_query.hpp b/library/trees/uncommon/contour_range_query.hpp
index 4e5d8b80..e2bf71fc 100644
--- a/library/trees/uncommon/contour_range_query.hpp
+++ b/library/trees/uncommon/contour_range_query.hpp
@@ -9,7 +9,7 @@ struct contour_range_query {
   vector<vector<array<int, 3>>> info;
   vector<array<BIT, 2>> bits;
   //! @param adj unrooted, undirected tree
-  //! @param a a[v] = initial number for node v
+  //! @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,
@@ -18,41 +18,40 @@ struct contour_range_query {
     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 v, int p, int d,
+        auto dfs = [&](auto&& self, int u, int p, int d,
                      int side) -> void {
-          info[v].push_back({int(sz(bits)), d, side});
+          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[v];
-          for (int u : cd_adj[v])
-            if (u != p) self(self, u, v, 1 + d, side);
+          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])});
       });
   }
-  //! @param v node
-  //! @param delta number to add to node v's number
+  //! @param u node
+  //! @param delta number to add to node u's number
   //! @time O(logφ(n) * log2(n))
   //! @space O(1)
-  void update(int v, ll delta) {
-    sum_a.update(v, delta);
-    for (auto [decomp, d, side] : info[v])
+  void update(int u, ll delta) {
+    sum_a.update(u, delta);
+    for (auto [decomp, d, side] : info[u])
       bits[decomp][side].update(d, delta);
   }
-  //! @param v node
+  //! @param u node
   //! @param l,r defines range [l, r)
-  //! @returns sum of node u's number over all u such that
-  //! l
-  //! <= dist_edges(u, v) < r
+  //! @returns sum of node v's number over all v such that
+  //! l <= dist(u, v) < r
   //! @time O(logφ(n) * log2(n))
   //! @space O(1)
-  ll query(int v, int l, int r) {
+  ll query(int u, int l, int r) {
     ll sum = 0;
-    if (l <= 0 && 0 < r) sum += sum_a.sum[v];
-    if (l <= 1 && 1 < r) sum += sum_a.query(v);
-    for (auto [decomp, d, side] : info[v]) {
+    if (l <= 0 && 0 < r) sum += sum_a.sum[u];
+    if (l <= 1 && 1 < r) sum += sum_a.query(u);
+    for (auto [decomp, d, side] : info[u]) {
       auto& bit = bits[decomp][!side];
       int my_l = clamp<int>(l - d, 1, sz(bit.s));
       int my_r = clamp<int>(r - d, 1, sz(bit.s));
diff --git a/library/trees/uncommon/contour_range_update.hpp b/library/trees/uncommon/contour_range_update.hpp
index c7972172..80f7bf1f 100644
--- a/library/trees/uncommon/contour_range_update.hpp
+++ b/library/trees/uncommon/contour_range_update.hpp
@@ -10,7 +10,7 @@ struct contour_range_update {
   vector<vector<array<int, 3>>> info;
   vector<array<bit_rupq, 2>> bits;
   //! @param adj unrooted, undirected tree
-  //! @param a a[v] = initial number for node v
+  //! @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,
@@ -19,12 +19,12 @@ struct contour_range_update {
     edge_cd(adj,
       [&](const vector<vi>& cd_adj, int cent, int split) {
         array<int, 2> mx_d = {0, 0};
-        auto dfs = [&](auto&& self, int v, int p, int d,
+        auto dfs = [&](auto&& self, int u, int p, int d,
                      int side) -> void {
           mx_d[side] = max(mx_d[side], d);
-          info[v].push_back({int(sz(bits)), d, side});
-          for (int u : cd_adj[v])
-            if (u != p) self(self, u, v, 1 + d, side);
+          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);
@@ -32,27 +32,27 @@ struct contour_range_update {
           {bit_rupq(mx_d[0] + 1), bit_rupq(mx_d[1] + 1)});
       });
   }
-  //! @param v,l,r,delta add delta to all nodes u such
-  //! that l <= dist_edges(v, u) < r
+  //! @param u,l,r,delta add delta to all nodes v such
+  //! that l <= dist(u, v) < r
   //! @time O(logφ(n) * log2(n))
   //! @space O(1)
-  void update(int v, int l, int r, ll delta) {
-    if (l <= 0 && 0 < r) a[v] += delta;
-    if (l <= 1 && 1 < r) sum_a.update(v, delta);
-    for (auto [decomp_id, d, side] : info[v]) {
+  void update(int u, int l, int r, ll delta) {
+    if (l <= 0 && 0 < r) a[u] += delta;
+    if (l <= 1 && 1 < r) sum_a.update(u, delta);
+    for (auto [decomp_id, d, side] : info[u]) {
       auto& bit = bits[decomp_id][!side];
       int my_l = clamp<int>(l - d, 1, bit.n);
       int my_r = clamp<int>(r - d, 1, bit.n);
       bit.update(my_l, my_r, delta);
     }
   }
-  //! @param v node
-  //! @returns number of node v
+  //! @param u node
+  //! @returns number of node u
   //! @time O(logφ(n) * log2(n))
   //! @space O(1)
-  ll query(int v) {
-    ll sum = a[v] + sum_a.query(v);
-    for (auto [decomp_id, d, side] : info[v])
+  ll query(int u) {
+    ll sum = a[u] + sum_a.query(u);
+    for (auto [decomp_id, d, side] : info[u])
       sum += bits[decomp_id][side].get_index(d);
     return sum;
   }
diff --git a/library/trees/uncommon/count_paths_per_length.hpp b/library/trees/uncommon/count_paths_per_length.hpp
index b98e0145..f1aec47a 100644
--- a/library/trees/uncommon/count_paths_per_length.hpp
+++ b/library/trees/uncommon/count_paths_per_length.hpp
@@ -13,12 +13,12 @@ vector<ll> count_paths_per_length(const vector<vi>& adj) {
   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 v, int p, int d,
+      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 u : cd_adj[v])
-          if (u != p) self(self, u, v, 1 + d, side);
+        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);
diff --git a/library/trees/uncommon/count_paths_per_node.hpp b/library/trees/uncommon/count_paths_per_node.hpp
index 9f96ca1c..21f7db17 100644
--- a/library/trees/uncommon/count_paths_per_node.hpp
+++ b/library/trees/uncommon/count_paths_per_node.hpp
@@ -14,16 +14,16 @@ vector<ll> count_paths_per_node(const vector<vi>& adj,
   centroid(adj,
     [&](const vector<vi>& cd_adj, int cent, int) {
       vector pre_d{1}, cur_d{0};
-      auto dfs = [&](auto&& self, int v, int p,
+      auto dfs = [&](auto&& self, int u, int p,
                    int d) -> ll {
         if (d > k) return 0LL;
         if (sz(cur_d) <= d) cur_d.push_back(0);
         cur_d[d]++;
         ll cnt = 0;
         if (k - d < sz(pre_d)) cnt += pre_d[k - d];
-        for (int u : cd_adj[v])
-          if (u != p) cnt += self(self, u, v, d + 1);
-        num_paths[v] += cnt;
+        for (int c : cd_adj[u])
+          if (c != p) cnt += self(self, c, u, d + 1);
+        num_paths[u] += cnt;
         return cnt;
       };
       auto dfs_child = [&](int child) -> ll {
diff --git a/library/trees/uncommon/ladder_decomposition.hpp b/library/trees/uncommon/ladder_decomposition.hpp
index 945d44aa..e0cb355a 100644
--- a/library/trees/uncommon/ladder_decomposition.hpp
+++ b/library/trees/uncommon/ladder_decomposition.hpp
@@ -5,7 +5,7 @@
 //! @code
 //!   ladder ld(adj);
 //!   // KACTL functions
-//!   int kth_par = jmp(ld.jmp, v, k);
+//!   int kth_par = jmp(ld.jmp, u, k);
 //!   int curr_lca = lca(ld.jmp, ld.d, u, v);
 //! @endcode
 struct ladder {
@@ -17,13 +17,13 @@ struct ladder {
   //! @space O(n log n) for jmp. Everything else is O(n)
   ladder(const auto& adj):
     n(sz(adj)), d(n), p(n), leaf(n), idx(n), lad(2 * n) {
-    auto dfs = [&](auto&& self, int v) -> void {
-      leaf[v] = v;
-      for (int u : adj[v])
-        if (u != p[v]) {
-          d[u] = d[p[u] = v] + 1;
-          self(self, u);
-          if (d[leaf[v]] < d[leaf[u]]) leaf[v] = leaf[u];
+    auto dfs = [&](auto&& self, int u) -> void {
+      leaf[u] = u;
+      for (int v : adj[u])
+        if (v != p[u]) {
+          d[v] = d[p[v] = u] + 1;
+          self(self, v);
+          if (d[leaf[u]] < d[leaf[v]]) leaf[u] = leaf[v];
         }
     };
     dfs(dfs, 0);
@@ -36,19 +36,19 @@ struct ladder {
     }
     jmp = treeJump(p);
   }
-  //! @param v query node
+  //! @param u query node
   //! @param k number of edges
-  //! @returns a node k edges up from v. With k=1, this
-  //! returns v's parent.
+  //! @returns a node k edges up from u. With k=1, this
+  //! returns u's parent.
   //! @time O(1)
   //! @space O(1)
-  int kth_par(int v, int k) {
-    assert(0 <= k && k <= d[v]);
-    if (k == 0) return v;
+  int kth_par(int u, int k) {
+    assert(0 <= k && k <= d[u]);
+    if (k == 0) return u;
     int bit = __lg(k);
-    v = jmp[bit][v], k -= (1 << bit);
-    int l = idx[leaf[v]] + d[leaf[v]] - d[v];
-    assert(lad[l] == v);
+    u = jmp[bit][u], k -= (1 << bit);
+    int l = idx[leaf[u]] + d[leaf[u]] - d[u];
+    assert(lad[l] == u);
     // subarray [l, l+k] of lad corresponds to the rest
     // of the jump
     return lad[l + k];
diff --git a/library/trees/uncommon/subtree_isomorphism.hpp b/library/trees/uncommon/subtree_isomorphism.hpp
index 784421f3..88ae9f8d 100644
--- a/library/trees/uncommon/subtree_isomorphism.hpp
+++ b/library/trees/uncommon/subtree_isomorphism.hpp
@@ -12,12 +12,12 @@
 auto subtree_iso(const auto& adj) {
   vi iso_id(sz(adj), -1);
   map<vi, int> hashes;
-  auto dfs = [&](auto&& self, int v, int p) -> int {
+  auto dfs = [&](auto&& self, int u, int p) -> int {
     vi ch_ids;
-    for (int u : adj[v])
-      if (u != p) ch_ids.push_back(self(self, u, v));
+    for (int v : adj[u])
+      if (v != p) ch_ids.push_back(self(self, v, u));
     ranges::sort(ch_ids);
-    return iso_id[v] =
+    return iso_id[u] =
              hashes.try_emplace(ch_ids, sz(hashes))
                .first->second;
   };
diff --git a/library/trees/uncommon/sum_adjacent.hpp b/library/trees/uncommon/sum_adjacent.hpp
index f54c3d00..623e5562 100644
--- a/library/trees/uncommon/sum_adjacent.hpp
+++ b/library/trees/uncommon/sum_adjacent.hpp
@@ -6,32 +6,32 @@ struct sum_adj {
   vector<ll> sum, sum_ch;
   vi p;
   //! @param adj undirected, unrooted tree
-  //! @param sum sum[v] = initial number for node v
+  //! @param sum sum[u] = initial number for node u
   //! @time O(n)
   //! @space various O(n) vectors are allocated; recursion
   //! stack for dfs is O(n)
   sum_adj(const vector<vi>& adj, const vector<ll>& sum):
     n(sz(sum)), sum(sum), sum_ch(n), p(n, -1) {
-    auto dfs = [&](auto&& self, int v) -> void {
-      for (int u : adj[v])
-        if (u != p[v])
-          p[u] = v, sum_ch[v] += sum[u], self(self, u);
+    auto dfs = [&](auto&& self, int u) -> void {
+      for (int c : adj[u])
+        if (c != p[u])
+          p[c] = u, sum_ch[u] += sum[c], self(self, c);
     };
     dfs(dfs, 0);
   }
-  //! @param v node
+  //! @param u node
   //! @param delta number to add
   //! @time O(1)
   //! @space O(1)
-  void update(int v, ll delta) {
-    sum[v] += delta;
-    if (p[v] != -1) sum_ch[p[v]] += delta;
+  void update(int u, ll delta) {
+    sum[u] += delta;
+    if (p[u] != -1) sum_ch[p[u]] += delta;
   }
-  //! @param v node
-  //! @returns sum of v's neighbors numbers
+  //! @param u node
+  //! @returns sum of u's neighbors numbers
   //! @time O(1)
   //! @space O(1)
-  ll query(int v) {
-    return sum_ch[v] + (p[v] != -1 ? sum[p[v]] : 0);
+  ll query(int u) {
+    return sum_ch[u] + (p[u] != -1 ? sum[p[u]] : 0);
   }
 };