make variable naming consistent across library (#223)

cameroncuster · Cameron Custer · web-flow · commit 962f6a66b70c · 2026-07-06T11:00:20.000-07:00
* make variable naming consistent across library

* apply naming conventions to doc examples

---------

Co-authored-by: Cameron Custer &lt;cam@augmentcode.com&gt;
diff --git a/library/data_structures_[l,r)/bit.hpp b/library/data_structures_[l,r)/bit.hpp
@@ -20,9 +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"
diff --git a/library/data_structures_[l,r)/bit_uncommon/kd_bit.hpp b/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> {
diff --git a/library/data_structures_[l,r)/seg_tree_uncommon/kth_smallest_query.hpp b/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);
   }
 };
diff --git a/library/data_structures_[l,r)/uncommon/deque_op.hpp b/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)) {
diff --git a/library/data_structures_[l,r)/uncommon/mode_query.hpp b/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]]--;
     }
diff --git a/library/data_structures_[l,r)/uncommon/priority_queue_of_updates.hpp b/library/data_structures_[l,r)/uncommon/priority_queue_of_updates.hpp
@@ -5,7 +5,7 @@
 //!   DS ds;
 //!   // int = argument type of DS::join
 //!   pq_updates<DS, int> pq(ds);
-//!   pq.push_update(val, priority);
+//!   pq.push_update(val, pri);
 //!   pq.pop_update();
 //! @endcode
 //! @time n interweaved calls to pop_update, push_update
@@ -38,10 +38,9 @@ template<class DS, class... ARGS> struct pq_updates {
       extra.push_back(upd_st[idx_sk]);
       idx = min(idx, idx_sk), lowest_pri = pri;
     }
-    auto it =
-      remove_if(idx + all(upd_st), [&](auto& curr) {
-        return curr.second->first >= lowest_pri;
-      });
+    auto it = remove_if(idx + all(upd_st), [&](auto& cur) {
+      return cur.second->first >= lowest_pri;
+    });
     reverse_copy(all(extra), it);
     rep(i, idx, sz(upd_st)) ds.undo();
     upd_st.pop_back();
@@ -53,13 +52,13 @@ template<class DS, class... ARGS> struct pq_updates {
     }
   }
   //! @param args arguments to DS::join
-  //! @param priority must be distinct, can be negative
+  //! @param pri must be distinct, can be negative
   //! @time O(log(n) + T(n))
   //! @space an new update is allocated, inserted into
   //! `upd_st`, `mp` member variables
-  void push_update(ARGS... args, int priority) {
+  void push_update(ARGS... args, int pri) {
     ds.join(args...);
-    auto [it, ins] = mp.emplace(priority, sz(upd_st));
+    auto [it, ins] = mp.emplace(pri, sz(upd_st));
     assert(ins);
     upd_st.emplace_back(make_tuple(args...), it);
   }
diff --git a/library/data_structures_[l,r]/bit.hpp b/library/data_structures_[l,r]/bit.hpp
@@ -20,9 +20,9 @@ struct BIT {
     for (; i < sz(s); i |= i + 1) s[i] += d;
   }
   ll query(int i) {
-    ll ret = 0;
-    for (; i >= 0; (i &= i + 1)--) ret += s[i];
-    return ret;
+    ll res = 0;
+    for (; i >= 0; (i &= i + 1)--) res += s[i];
+    return res;
   }
   ll query(int l, int r) {
     return query(r) - query(l - 1);
diff --git a/library/dsu/line_tree.hpp b/library/dsu/line_tree.hpp
@@ -5,10 +5,10 @@
 //!   line_tree lt(n);
 //!   for (auto [w, u, v] : w_eds) lt.join(u, v);
 //!   for (int v = lt.f(0); v != -1;) {
-//!     auto [next, e_id] = lt.edge[v];
+//!     auto [nxt, e_id] = lt.edge[v];
 //!     int w = w_eds[e_id][0];
 //!     //
-//!     v = next;
+//!     v = nxt;
 //!   }
 //! @endcode
 //! lt.f(v) = head of linked list
diff --git a/library/flow/hungarian.hpp b/library/flow/hungarian.hpp
@@ -18,18 +18,18 @@ pair<ll, vi> hungarian(const vector<vector<ll>>& cost) {
     p[0] = i;
     int j0 = 0;
     vector minv(m, LLONG_MAX);
-    vi used(m);
+    vi vis(m);
     do {
-      used[j0] = 1;
+      vis[j0] = 1;
       int i0 = p[j0], j1 = 0;
       ll delta = LLONG_MAX;
-      rep(j, 1, m) if (!used[j]) {
+      rep(j, 1, m) if (!vis[j]) {
         ll cur = cost[i0][j] - u[i0] - v[j];
         if (cur < minv[j]) minv[j] = cur, way[j] = j0;
         if (minv[j] < delta) delta = minv[j], j1 = j;
       }
       rep(j, 0, m) {
-        if (used[j]) u[p[j]] += delta, v[j] -= delta;
+        if (vis[j]) u[p[j]] += delta, v[j] -= delta;
         else minv[j] -= delta;
       }
       j0 = j1;
diff --git a/library/graphs/bcc_callback.hpp b/library/graphs/bcc_callback.hpp
@@ -4,17 +4,17 @@
 //!   {
 //!     vector<vi> g(n);
 //!     DSU dsu(n);
-//!     vector<bool> seen(n);
+//!     vector<bool> vis(n);
 //!     bcc(g, [&](const vi& nodes) {
-//!       int count_edges = 0;
+//!       int cnt_edges = 0;
 //!       rep (i, 0, sz(nodes) - 1) {
-//!         seen[nodes[i]] = 1;
-//!         for (int u : g[nodes[i]]) if (!seen[u]) {
+//!         vis[nodes[i]] = 1;
+//!         for (int u : g[nodes[i]]) if (!vis[u]) {
 //!           // edge nodes[i] <=> u is in current BCC
-//!           count_edges++;
+//!           cnt_edges++;
 //!         }
 //!       }
-//!       if (count_edges == 1) {
+//!       if (cnt_edges == 1) {
 //!         // nodes[0] <=> nodes[1] is a bridge
 //!         return;
 //!       }
diff --git a/library/graphs/uncommon/enumerate_triangles.hpp b/library/graphs/uncommon/enumerate_triangles.hpp
@@ -16,11 +16,11 @@ void enumerate_triangles(const vector<pii>& edges, int n,
     if (tie(deg[u], u) > tie(deg[v], v)) swap(u, v);
     g[u].push_back(v);
   }
-  vector<bool> seen(n);
+  vector<bool> vis(n);
   for (auto [u, v] : edges) {
-    for (int w : g[u]) seen[w] = 1;
+    for (int w : g[u]) vis[w] = 1;
     for (int w : g[v])
-      if (seen[w]) f(u, v, w);
-    for (int w : g[u]) seen[w] = 0;
+      if (vis[w]) f(u, v, w);
+    for (int w : g[u]) vis[w] = 0;
   }
 }
diff --git a/library/math/count_paths/count_paths_rectangle.hpp b/library/math/count_paths/count_paths_rectangle.hpp
@@ -8,13 +8,13 @@
 //! @time O((n + m)log(n + m))
 //! @space O(n + m)
 array<vl, 2> get_right_and_top(vl left, vl bottom) {
-  array<vl, 2> ret;
-  for (vl& res : ret) {
+  array<vl, 2> res;
+  for (vl& cur : res) {
     {
       vl tr(sz(left));
       rep(i, 0, sz(tr)) tr[i] = C(i + sz(bottom) - 1, i);
-      res = conv(left, tr);
-      res.resize(sz(left));
+      cur = conv(left, tr);
+      cur.resize(sz(left));
     }
     {
       vl tr(sz(left) + sz(bottom));
@@ -23,13 +23,13 @@ array<vl, 2> get_right_and_top(vl left, vl bottom) {
       vl dp(sz(bottom));
       rep(i, 0, sz(dp)) dp[i] =
         bottom[i] * t[sz(dp) - 1 - i].inv_fact % mod;
-      vl tmp_res = conv(dp, tr);
-      rep(i, 0, sz(res))
-        res[i] = (res[i] + tmp_res[i + sz(bottom) - 1] *
+      vl tmp = conv(dp, tr);
+      rep(i, 0, sz(cur))
+        cur[i] = (cur[i] + tmp[i + sz(bottom) - 1] *
                              t[i].inv_fact) %
                  mod;
     }
     swap(left, bottom);
   }
-  return ret;
+  return res;
 }
diff --git a/library/math/num_distinct_subsequences.hpp b/library/math/num_distinct_subsequences.hpp
@@ -7,12 +7,12 @@ int num_subsequences(const vi& a, int mod) {
   vector dp(sz(a) + 1, 1);
   map<int, int> last;
   rep(i, 0, sz(a)) {
-    int& curr = dp[i + 1] = 2 * dp[i];
-    if (curr >= mod) curr -= mod;
+    int& cur = dp[i + 1] = 2 * dp[i];
+    if (cur >= mod) cur -= mod;
     auto it = last.find(a[i]);
     if (it != end(last)) {
-      curr -= dp[it->second];
-      if (curr < 0) curr += mod;
+      cur -= dp[it->second];
+      if (cur < 0) cur += mod;
       it->second = i;
     } else last[a[i]] = i;
   }
diff --git a/library/strings/binary_trie.hpp b/library/strings/binary_trie.hpp
@@ -10,19 +10,19 @@ const ll mx_bit = 1LL << 60;
 struct binary_trie {
   struct node {
     int siz = 0;
-    array<int, 2> next = {-1, -1};
+    array<int, 2> nxt = {-1, -1};
   };
   deque<node> t;
   binary_trie(): t(1) {}
   void update(ll num, int delta) {
     int v = 0;
     for (ll bit = mx_bit; bit; bit /= 2) {
       bool b = num & bit;
-      if (t[v].next[b] == -1) {
-        t[v].next[b] = sz(t);
+      if (t[v].nxt[b] == -1) {
+        t[v].nxt[b] = sz(t);
         t.emplace_back();
       }
-      v = t[v].next[b];
+      v = t[v].nxt[b];
       t[v].siz += delta;
     }
   }
@@ -31,9 +31,9 @@ struct binary_trie {
     ll res = 0;
     for (ll bit = mx_bit; bit; bit /= 2) {
       bool b = num & bit;
-      int u = t[v].next[b];
+      int u = t[v].nxt[b];
       if (u != -1 && t[u].siz > 0) v = u, res |= num & bit;
-      else v = t[v].next[!b], res |= (~num) & bit;
+      else v = t[v].nxt[!b], res |= (~num) & bit;
     }
     return res;
   }
diff --git a/library/strings/trie.hpp b/library/strings/trie.hpp
@@ -3,30 +3,30 @@
 const int mn = 'A';
 struct trie {
   struct node {
-    array<int, 26> next;
+    array<int, 26> nxt;
     bool end_of_word = 0;
-    node() { ranges::fill(next, -1); }
+    node() { ranges::fill(nxt, -1); }
   };
   deque<node> t;
   trie(): t(1) {}
   void insert(const string& s) {
     int v = 0;
     for (char ch : s) {
       int u = ch - mn;
-      if (t[v].next[u] == -1) {
-        t[v].next[u] = sz(t);
+      if (t[v].nxt[u] == -1) {
+        t[v].nxt[u] = sz(t);
         t.emplace_back();
       }
-      v = t[v].next[u];
+      v = t[v].nxt[u];
     }
     t[v].end_of_word = 1;
   }
   int find(const string& s) {
     int v = 0;
     for (char ch : s) {
       int u = ch - mn;
-      if (t[v].next[u] == -1) return 0;
-      v = t[v].next[u];
+      if (t[v].nxt[u] == -1) return 0;
+      v = t[v].nxt[u];
     }
     return t[v].end_of_word;
   }
diff --git a/tests/library_checker_aizu_tests/data_structures/binary_trie.test.cpp b/tests/library_checker_aizu_tests/data_structures/binary_trie.test.cpp
@@ -18,11 +18,10 @@ int main() {
     int type, x;
     cin >> type >> x;
     if (type == 0) {
-      if (
-        bt.t[bt.t[0].next[0]].siz == 0 || bt.walk(x) != x)
+      if (bt.t[bt.t[0].nxt[0]].siz == 0 || bt.walk(x) != x)
         bt.update(x, 1);
     } else if (type == 1) {
-      if (bt.t[bt.t[0].next[0]].siz > 0 && bt.walk(x) == x)
+      if (bt.t[bt.t[0].nxt[0]].siz > 0 && bt.walk(x) == x)
         bt.update(x, -1);
     } else {
       assert(type == 2);

Original file line number	Diff line number	Diff line change
`@@ -20,9 +20,9 @@ struct BIT {`
`20`	`20`	`for (; i < sz(s); i \|= i + 1) s[i] += d;`
`21`	`21`	`}`
`22`	`22`	`ll query(int r) {`
`23`		`- ll ret = 0;`
`24`		`- for (; r > 0; r &= r - 1) ret += s[r - 1];`
`25`		`- return ret;`
	`23`	`+ ll res = 0;`
	`24`	`+ for (; r > 0; r &= r - 1) res += s[r - 1];`
	`25`	`+ return res;`
`26`	`26`	`}`
`27`	`27`	`ll query(int l, int r) { return query(r) - query(l); }`
`28`	`28`	`#include "bit_uncommon/walk_lambda.hpp"`
Original file line number	Diff line number	Diff line change
`@@ -24,9 +24,9 @@ template<class T, class F> struct deq {`
`24`	`24`	`T front() { return (empty(l) ? r[0] : l.back())[0]; }`
`25`	`25`	`T back() { return (empty(r) ? l[0] : r.back())[0]; }`
`26`	`26`	`int siz() { return sz(l) + sz(r); }`
`27`		`- void push_back(T elem) {`
	`27`	`+ void push_back(T val) {`
`28`	`28`	`r.push_back(`
`29`		`- {elem, empty(r) ? elem : op(r.back()[1], elem)});`
	`29`	`+ {val, empty(r) ? val : op(r.back()[1], val)});`
`30`	`30`	`}`
`31`	`31`	`void pop_back() {`
`32`	`32`	`if (empty(r)) {`
`@@ -37,9 +37,9 @@ template<class T, class F> struct deq {`
`37`	`37`	`}`
`38`	`38`	`r.pop_back();`
`39`	`39`	`}`
`40`		`- void push_front(T elem) {`
	`40`	`+ void push_front(T val) {`
`41`	`41`	`l.push_back(`
`42`		`- {elem, empty(l) ? elem : op(elem, l.back()[1])});`
	`42`	`+ {val, empty(l) ? val : op(val, l.back()[1])});`
`43`	`43`	`}`
`44`	`44`	`void pop_front() {`
`45`	`45`	`if (empty(l)) {`