diff --git a/src/1-ds/ds_segtree.cpp b/src/1-ds/ds_segtree.cpp
index 39644e4..ce605c3 100644
--- a/src/1-ds/ds_segtree.cpp
+++ b/src/1-ds/ds_segtree.cpp
@@ -235,8 +235,8 @@ struct seg_2d { // 1-indexed
 
 // what: 2D segment tree with coordinate compression for sparse updates/queries.
 // time: prep O(q log q), update/query O(log^2 n); memory: O(q log q)
-// constraint: x is 1-indexed [1..n]; y is coordinate value; call mark_set/mark_qry first, then prep, then set/query.
-// usage: seg2d_comp st(n); st.mark_set(x, y); st.mark_qry(x1, x2, y1, y2); st.prep(); st.set(x, y, v); st.query(x1, x2, y1, y2);
+// constraint: x is 1-indexed [1..n]; y is coordinate value; call mark_set/mark_query first, then prep, then set/query.
+// usage: seg2d_comp st(n); st.mark_set(x, y); st.mark_query(x1, x2, y1, y2); st.prep(); st.set(x, y, v); st.query(x1, x2, y1, y2);
 struct seg2d_comp { // x: 1-indexed
     int n;
     vector<vector<ll>> a;
@@ -247,7 +247,7 @@ struct seg2d_comp { // x: 1-indexed
         // goal: record y-coordinates that will be updated.
         for (x += n - 1; x >= 1; x >>= 1) used[x].push_back(y);
     }
-    void mark_qry(int x1, int x2, int y1, int y2) {
+    void mark_query(int x1, int x2, int y1, int y2) {
         // goal: record y-coordinates needed for queries.
         for (x1 += n - 1, x2 += n; x1 < x2; x1 >>= 1, x2 >>= 1) {
             if (x1 & 1) {
diff --git a/src/2-graph/cc_bcc.cpp b/src/2-graph/cc_bcc.cpp
index 663325f..babfd25 100644
--- a/src/2-graph/cc_bcc.cpp
+++ b/src/2-graph/cc_bcc.cpp
@@ -3,7 +3,7 @@
 // what: find biconnected components and articulation points/bridges in an undirected graph.
 // time: O(n+m); memory: O(n+m)
 // constraint: 1-indexed; no self-loops; recursion depth O(n).
-// usage: bcc_graph g; g.init(n); g.add(u,v); g.run(); // g.bccs, g.ap, g.ae
+// usage: bcc_graph g; g.init(n); g.add_edge(u,v); g.run(); // g.bccs, g.ap, g.ae
 struct bcc_graph {
     int n, tim;
     vector<vector<pii>> adj;
@@ -23,7 +23,7 @@ struct bcc_graph {
         ed.clear();
         bccs.clear();
     }
-    void add(int u, int v) {
+    void add_edge(int u, int v) {
         int id = sz(ed);
         ed.push_back({u, v});
         adj[u].push_back({v, id});
diff --git a/src/2-graph/cc_scc.cpp b/src/2-graph/cc_scc.cpp
index 492e584..66428fd 100644
--- a/src/2-graph/cc_scc.cpp
+++ b/src/2-graph/cc_scc.cpp
@@ -3,7 +3,7 @@
 // what: compute SCCs in a directed graph using Kosaraju's algorithm.
 // time: O(n+m); memory: O(n+m)
 // constraint: directed; 1-indexed; recursion depth O(n).
-// usage: scc_kosa s; s.init(n); s.add(u,v); int c=s.run();
+// usage: scc_kosa s; s.init(n); s.add_edge(u,v); int c=s.run();
 struct scc_kosa {
     int n;
     vector<vector<int>> g, rg, sccs;
@@ -18,7 +18,7 @@ struct scc_kosa {
         comp.assign(n + 1, -1);
         ord.clear();
     }
-    void add(int u, int v) {
+    void add_edge(int u, int v) {
         g[u].push_back(v);
         rg[v].push_back(u);
     }
@@ -50,7 +50,7 @@ struct scc_kosa {
 // what: compute SCCs in a directed graph using Tarjan's algorithm.
 // time: O(n+m); memory: O(n+m)
 // constraint: directed; 1-indexed; recursion depth O(n).
-// usage: scc_tarjan s; s.init(n); s.add(u,v); int c=s.run();
+// usage: scc_tarjan s; s.init(n); s.add_edge(u,v); int c=s.run();
 struct scc_tarjan {
     int n, tim;
     vector<vector<int>> g, sccs;
@@ -67,7 +67,7 @@ struct scc_tarjan {
         ins.assign(n + 1, 0);
         st.clear();
     }
-    void add(int u, int v) { g[u].push_back(v); }
+    void add_edge(int u, int v) { g[u].push_back(v); }
     void dfs(int v) {
         dfn[v] = low[v] = ++tim;
         st.push_back(v);
diff --git a/src/2-graph/euler_circ.cpp b/src/2-graph/euler_circ.cpp
index f1d944a..d70060a 100644
--- a/src/2-graph/euler_circ.cpp
+++ b/src/2-graph/euler_circ.cpp
@@ -3,7 +3,7 @@
 // what: build an Eulerian circuit in an undirected multigraph (adjacency matrix).
 // time: O(n^2+m); memory: O(n^2)
 // constraint: 1-indexed; all nonzero-degree nodes connected.
-// usage: euler_cir g; g.init(n); g.add(u,v); if (g.can()) auto path=g.run(1);
+// usage: euler_cir g; g.init(n); g.add_edge(u,v); if (g.can()) auto path=g.run(1);
 struct euler_cir {
     int n;
     vector<vector<int>> adj;
@@ -16,7 +16,7 @@ struct euler_cir {
         nxt.assign(n + 1, 1);
         path.clear();
     }
-    void add(int u, int v, int c = 1) {
+    void add_edge(int u, int v, int c = 1) {
         // goal: add c parallel edges between u and v.
         if (u == v) adj[u][u] += 2 * c;
         else adj[u][v] += c, adj[v][u] += c;
diff --git a/src/2-graph/sp_basic.cpp b/src/2-graph/sp_basic.cpp
index a68946d..ecc7b24 100644
--- a/src/2-graph/sp_basic.cpp
+++ b/src/2-graph/sp_basic.cpp
@@ -3,7 +3,7 @@
 // what: compute single-source shortest paths with non-negative edges (Dijkstra).
 // time: O((n+m)log n); memory: O(n+m)
 // constraint: directed; 1-indexed; w >= 0.
-// usage: dijkstra g; g.init(n); g.add(u,v,w); auto dist=g.run(s);
+// usage: dijkstra g; g.init(n); g.add_edge(u,v,w); auto dist=g.run(s);
 struct dijkstra {
     static const ll INF = (1LL << 62);
     int n;
@@ -14,7 +14,7 @@ struct dijkstra {
         n = n_;
         adj.assign(n + 1, {});
     }
-    void add(int u, int v, ll w) { adj[u].push_back({w, v}); }
+    void add_edge(int u, int v, ll w) { adj[u].push_back({w, v}); }
     vector<ll> run(int s) {
         // result: dist[i] = shortest distance from s to i.
         vector<ll> dist(n + 1, INF);
@@ -39,7 +39,7 @@ struct dijkstra {
 // what: compute single-source shortest paths with possible negative edges.
 // time: O(nm); memory: O(n+m)
 // constraint: directed; 1-indexed; detects negative cycle reachable from s.
-// usage: bell_ford g; g.init(n); g.add(u,v,w); bool ok=g.run(s, dist);
+// usage: bell_ford g; g.init(n); g.add_edge(u,v,w); bool ok=g.run(s, dist);
 struct bell_ford {
     static const ll INF = (1LL << 62);
     int n;
@@ -50,7 +50,7 @@ struct bell_ford {
         n = n_;
         ed.clear();
     }
-    void add(int u, int v, ll w) { ed.push_back({u, v, w}); }
+    void add_edge(int u, int v, ll w) { ed.push_back({u, v, w}); }
     bool run(int s, vector<ll> &dist) {
         // result: false if a negative cycle is reachable.
         dist.assign(n + 1, INF);
@@ -74,7 +74,7 @@ struct bell_ford {
 // what: compute all-pairs shortest paths with dynamic programming.
 // time: O(n^3); memory: O(n^2)
 // constraint: directed; 1-indexed; watch overflow on INF.
-// usage: floyd g; g.init(n); g.add(u,v,w); g.run(); auto &d=g.d;
+// usage: floyd g; g.init(n); g.add_edge(u,v,w); g.run(); auto &d=g.d;
 struct floyd {
     static const ll INF = (1LL << 62);
     int n;
@@ -86,7 +86,7 @@ struct floyd {
         d.assign(n + 1, vector<ll>(n + 1, INF));
         for (int i = 1; i <= n; i++) d[i][i] = 0;
     }
-    void add(int u, int v, ll w) { d[u][v] = min(d[u][v], w); }
+    void add_edge(int u, int v, ll w) { d[u][v] = min(d[u][v], w); }
     void run() {
         // goal: relax all pairs via intermediate nodes.
         for (int k = 1; k <= n; k++) {
diff --git a/src/2-graph/sp_kth.cpp b/src/2-graph/sp_kth.cpp
index 6738fbb..a808181 100644
--- a/src/2-graph/sp_kth.cpp
+++ b/src/2-graph/sp_kth.cpp
@@ -3,7 +3,7 @@
 // what: enumerate k-th shortest walk from s to t with non-negative weights (Eppstein-style).
 // time: O((n+m)log m + klog k); memory: O(n+m+heap)
 // constraint: 1-indexed; w >= 0; n <= MAXN-1; recursion depth O(log m).
-// usage: kth_walk g; g.init(n); g.add(u,v,w); auto v=g.run(s,e,k);
+// usage: kth_walk g; g.init(n); g.add_edge(u,v,w); auto v=g.run(s,e,k);
 struct kth_walk {
     static const int MAXN = 303030;
     static const ll INF = (ll)1e18;
@@ -42,7 +42,7 @@ struct kth_walk {
         for (int i = 1; i <= n; i++) g[i].clear(), rg[i].clear();
         hp.init();
     }
-    void add(int u, int v, ll w) {
+    void add_edge(int u, int v, ll w) {
         g[u].push_back({w, v});
         rg[v].push_back({w, u});
     }
diff --git a/src/3-tree/lca_sparse.cpp b/src/3-tree/lca_sparse.cpp
index 394ae24..198342b 100644
--- a/src/3-tree/lca_sparse.cpp
+++ b/src/3-tree/lca_sparse.cpp
@@ -3,7 +3,7 @@
 // what: LCA via binary lifting for rooted tree.
 // time: build O(n log n), query O(log n); memory: O(n log n)
 // constraint: 1-indexed tree.
-// usage: lca_sparse l; l.init(n); l.add(u,v); l.build(1); int w=l.lca(u,v);
+// usage: lca_sparse l; l.init(n); l.add_edge(u,v); l.build(1); int w=l.lca(u,v);
 struct lca_sparse {
     int n, lg;
     vector<vector<int>> adj, up;
@@ -17,7 +17,7 @@ struct lca_sparse {
         up.assign(lg, vector<int>(n + 1, 0));
         dep.assign(n + 1, 0);
     }
-    void add(int u, int v) {
+    void add_edge(int u, int v) {
         adj[u].push_back(v);
         adj[v].push_back(u);
     }
diff --git a/src/3-tree/tree_centroid.cpp b/src/3-tree/tree_centroid.cpp
index 62e6da9..34e3202 100644
--- a/src/3-tree/tree_centroid.cpp
+++ b/src/3-tree/tree_centroid.cpp
@@ -3,7 +3,7 @@
 // what: centroid decomposition for tree, builds centroid parent/children for path queries.
 // time: O(n log n); memory: O(n)
 // constraint: 1-indexed tree.
-// usage: cen_decomp cd; cd.init(n); cd.add(u,v); cd.build(); int p=cd.par[v];
+// usage: cen_decomp cd; cd.init(n); cd.add_edge(u,v); cd.build(); int p=cd.par[v];
 struct cen_decomp {
     int n;
     vector<vector<int>> adj, chd;
@@ -18,7 +18,7 @@ struct cen_decomp {
         siz.assign(n + 1, 0);
         used.assign(n + 1, 0);
     }
-    void add(int u, int v) {
+    void add_edge(int u, int v) {
         adj[u].push_back(v);
         adj[v].push_back(u);
     }
diff --git a/src/3-tree/tree_hld.cpp b/src/3-tree/tree_hld.cpp
index fcd8f9a..52e63e1 100644
--- a/src/3-tree/tree_hld.cpp
+++ b/src/3-tree/tree_hld.cpp
@@ -3,7 +3,7 @@
 // what: heavy-light decomposition for path sum on tree (node values).
 // time: build O(n), update/query O(log^2 n); memory: O(n)
 // constraint: 1-indexed tree.
-// usage: hld_tree h; h.init(n); h.add(u,v); h.build(1); h.set(v,x); ll s=h.qry(u,v);
+// usage: hld_tree h; h.init(n); h.add_edge(u,v); h.build(1); h.set(v,x); ll s=h.query(u,v);
 struct hld_tree {
     seg_tree seg;
 
@@ -22,7 +22,7 @@ struct hld_tree {
         top.assign(n + 1, 0);
         in.assign(n + 1, 0);
     }
-    void add(int u, int v) {
+    void add_edge(int u, int v) {
         adj[u].push_back(v);
         adj[v].push_back(u);
     }
@@ -55,7 +55,7 @@ struct hld_tree {
         seg.build(a);
     }
     void set(int v, ll val) { seg.set(in[v], val); }
-    ll qry(int a, int b) const {
+    ll query(int a, int b) const {
         ll ret = 0;
         while (top[a] != top[b]) {
             if (dep[top[a]] < dep[top[b]]) swap(a, b);
diff --git a/src/3-tree/tree_vtree.cpp b/src/3-tree/tree_vtree.cpp
index 4affd1f..04b2a69 100644
--- a/src/3-tree/tree_vtree.cpp
+++ b/src/3-tree/tree_vtree.cpp
@@ -3,7 +3,7 @@
 // what: virtual tree builder for subset DP using LCA and dfs order.
 // time: build O(n log n), make O(k log k); memory: O(n log n)
 // constraint: 1-indexed tree.
-// usage: tree_comp tc; tc.init(n); tc.add(u,v); tc.build(root); auto nodes=tc.make(vs); // use tc.vt_adj
+// usage: tree_comp tc; tc.init(n); tc.add_edge(u,v); tc.build(root); auto nodes=tc.make(vs); // use tc.vt_adj
 struct tree_comp {
     int n, lg, tim;
     vector<vector<int>> adj, up, vt_adj;
@@ -21,7 +21,7 @@ struct tree_comp {
         dep.assign(n + 1, 0);
         tim = 0;
     }
-    void add(int u, int v) {
+    void add_edge(int u, int v) {
         adj[u].push_back(v);
         adj[v].push_back(u);
     }
diff --git a/src/3-tree/tree_xchg.cpp b/src/3-tree/tree_xchg.cpp
index 6e9ecf8..b660b56 100644
--- a/src/3-tree/tree_xchg.cpp
+++ b/src/3-tree/tree_xchg.cpp
@@ -3,7 +3,7 @@
 // what: maximize sum w[i]*completion_time[i] under precedence "parent before child" on rooted tree.
 // time: O(n log n); memory: O(n)
 // constraint: 1-indexed tree; cw[i]=w[i]*t[i].
-// usage: tree_xchg tx; tx.init(n, root); tx.add(u,v); // set tx.ds.w/t/cw; ll ans=tx.run();
+// usage: tree_xchg tx; tx.init(n, root); tx.add_edge(u,v); // set tx.ds.w/t/cw; ll ans=tx.run();
 struct tree_xchg {
     struct uf {
         vector<int> par;
@@ -42,7 +42,7 @@ struct tree_xchg {
         par.assign(n + 1, 0);
         ds.init(n);
     }
-    void add(int u, int v) {
+    void add_edge(int u, int v) {
         adj[u].push_back(v);
         adj[v].push_back(u);
     }
diff --git a/tests/1-ds/test_ds_segtree.cpp b/tests/1-ds/test_ds_segtree.cpp
index 1b05397..ebf5d81 100644
--- a/tests/1-ds/test_ds_segtree.cpp
+++ b/tests/1-ds/test_ds_segtree.cpp
@@ -248,7 +248,7 @@ void test_seg2dc_basic() {
 
     for (auto &op : ops) {
         if (op.type == 0) st.mark_set(op.x1, op.y1);
-        else st.mark_qry(op.x1, op.x2, op.y1, op.y2);
+        else st.mark_query(op.x1, op.x2, op.y1, op.y2);
     }
     st.prep();
 
@@ -294,7 +294,7 @@ void test_seg2dc_random() {
 
     for (auto &op : ops) {
         if (op.type == 0) st.mark_set(op.x1, op.y1);
-        else st.mark_qry(op.x1, op.x2, op.y1, op.y2);
+        else st.mark_query(op.x1, op.x2, op.y1, op.y2);
     }
     st.prep();
 
diff --git a/tests/2-graph/test_cc_bcc.cpp b/tests/2-graph/test_cc_bcc.cpp
index 41a3fae..838b66b 100644
--- a/tests/2-graph/test_cc_bcc.cpp
+++ b/tests/2-graph/test_cc_bcc.cpp
@@ -109,7 +109,7 @@ void t_fix() {
     vector<pii> ed = {{1, 2}, {2, 3}};
     bcc_graph g;
     g.init(n);
-    for (auto [u, v] : ed) g.add(u, v);
+    for (auto [u, v] : ed) g.add_edge(u, v);
     g.run();
     auto ap = g.ap;
     auto ae = g.ae;
@@ -135,7 +135,7 @@ void t_rnd() {
         }
         bcc_graph g;
         g.init(n);
-        for (auto [u, v] : ed) g.add(u, v);
+        for (auto [u, v] : ed) g.add_edge(u, v);
         g.run();
         auto ap = g.ap;
         auto ae = g.ae;
diff --git a/tests/2-graph/test_cc_scc.cpp b/tests/2-graph/test_cc_scc.cpp
index 278eea1..8c8960e 100644
--- a/tests/2-graph/test_cc_scc.cpp
+++ b/tests/2-graph/test_cc_scc.cpp
@@ -55,13 +55,13 @@ void t_scc() {
         scc_kosa s1;
         s1.init(n);
         for (int u = 1; u <= n; u++)
-            for (int v : g[u]) s1.add(u, v);
+            for (int v : g[u]) s1.add_edge(u, v);
         s1.run();
 
         scc_tarjan s2;
         s2.init(n);
         for (int u = 1; u <= n; u++)
-            for (int v : g[u]) s2.add(u, v);
+            for (int v : g[u]) s2.add_edge(u, v);
         s2.run();
 
         for (int i = 1; i <= n; i++)
diff --git a/tests/2-graph/test_euler_circ.cpp b/tests/2-graph/test_euler_circ.cpp
index c030326..451255a 100644
--- a/tests/2-graph/test_euler_circ.cpp
+++ b/tests/2-graph/test_euler_circ.cpp
@@ -54,7 +54,7 @@ bool can_na(int n, const vector<vector<int>> &cnt) {
 }
 
 void add_ed(euler_cir &g, vector<vector<int>> &cnt, int u, int v) {
-    g.add(u, v);
+    g.add_edge(u, v);
     if (u == v) cnt[u][u]++;
     else cnt[u][v]++, cnt[v][u]++;
 }
diff --git a/tests/2-graph/test_sp_basic.cpp b/tests/2-graph/test_sp_basic.cpp
index 12b8070..65f2347 100644
--- a/tests/2-graph/test_sp_basic.cpp
+++ b/tests/2-graph/test_sp_basic.cpp
@@ -37,7 +37,7 @@ void t_dijk() {
             int u = rnd(1, n), v = rnd(1, n);
             ll w = rnd(0, 9);
             ed.push_back({u, v, w});
-            dj.add(u, v, w);
+            dj.add_edge(u, v, w);
         }
         auto d = floy(n, ed);
         int s = rnd(1, n);
@@ -63,7 +63,7 @@ void t_bell() {
             int u = rnd(1, n), v = rnd(1, n);
             ll w = rnd(-5, 9);
             ed.push_back({u, v, w});
-            bl.add(u, v, w);
+            bl.add_edge(u, v, w);
         }
         auto d = floy(n, ed);
         int s = rnd(1, n);
@@ -98,7 +98,7 @@ void t_floy() {
             int u = rnd(1, n), v = rnd(1, n);
             ll w = rnd(-5, 9);
             ed.push_back({u, v, w});
-            fl.add(u, v, w);
+            fl.add_edge(u, v, w);
         }
         auto d = floy(n, ed);
         bool neg = 0;
diff --git a/tests/2-graph/test_sp_kth.cpp b/tests/2-graph/test_sp_kth.cpp
index 1b7d0ca..6e93654 100644
--- a/tests/2-graph/test_sp_kth.cpp
+++ b/tests/2-graph/test_sp_kth.cpp
@@ -36,8 +36,8 @@ void t_fix() {
     g[1].push_back({1, 2});
     g[2].push_back({1, 3});
     ks.init(n);
-    ks.add(1, 2, 1);
-    ks.add(2, 3, 1);
+    ks.add_edge(1, 2, 1);
+    ks.add_edge(2, 3, 1);
     auto a = kth_na(n, g, 1, 3, 3);
     auto b = ks.run(1, 3, 3);
     assert(a == b);
@@ -53,7 +53,7 @@ void t_rnd() {
             int u = rnd(1, n), v = rnd(1, n);
             ll w = rnd(1, 5);
             g[u].push_back({w, v});
-            ks.add(u, v, w);
+            ks.add_edge(u, v, w);
         }
         int s = rnd(1, n), e = rnd(1, n), k = rnd(1, 10);
         auto a = kth_na(n, g, s, e, k);
diff --git a/tests/3-tree/test_lca_sparse.cpp b/tests/3-tree/test_lca_sparse.cpp
index 25a0d35..924d17e 100644
--- a/tests/3-tree/test_lca_sparse.cpp
+++ b/tests/3-tree/test_lca_sparse.cpp
@@ -44,7 +44,7 @@ void t_rnd() {
         }
         lca_sparse l;
         l.init(n);
-        for (int v = 2; v <= n; v++) l.add(v, par[v]);
+        for (int v = 2; v <= n; v++) l.add_edge(v, par[v]);
         l.build(1);
         for (int q = 0; q < 50; q++) {
             int a = rnd(1, n), b = rnd(1, n);
diff --git a/tests/3-tree/test_tree_centroid.cpp b/tests/3-tree/test_tree_centroid.cpp
index 4a4d2bf..7840e0d 100644
--- a/tests/3-tree/test_tree_centroid.cpp
+++ b/tests/3-tree/test_tree_centroid.cpp
@@ -59,7 +59,7 @@ void check_one(const vector<vector<int>> &adj) {
     cd.init(n);
     for (int u = 1; u <= n; u++)
         for (int v : adj[u])
-            if (u < v) cd.add(u, v);
+            if (u < v) cd.add_edge(u, v);
     cd.build(1);
 
     int root = get_root(n, cd.par);
diff --git a/tests/3-tree/test_tree_hld.cpp b/tests/3-tree/test_tree_hld.cpp
index 2f92e04..c09035d 100644
--- a/tests/3-tree/test_tree_hld.cpp
+++ b/tests/3-tree/test_tree_hld.cpp
@@ -51,14 +51,14 @@ void t_fix() {
     h.init(n);
     for (int u = 1; u <= n; u++)
         for (int v : adj[u])
-            if (u < v) h.add(u, v);
+            if (u < v) h.add_edge(u, v);
     h.build(1);
     vector<ll> val = {0, 1, 2, 3, 4};
     for (int i = 1; i <= n; i++) h.set(i, val[i]);
     auto p = path_nodes(n, adj, 3, 4);
     ll sum = 0;
     for (int v : p) sum += val[v];
-    assert(h.qry(3, 4) == sum);
+    assert(h.query(3, 4) == sum);
 }
 
 void t_rnd() {
@@ -73,7 +73,7 @@ void t_rnd() {
         }
         hld_tree h;
         h.init(n);
-        for (int v = 2; v <= n; v++) h.add(v, par[v]);
+        for (int v = 2; v <= n; v++) h.add_edge(v, par[v]);
         h.build(1);
         vector<ll> val(n + 1);
         for (int i = 1; i <= n; i++) {
@@ -85,7 +85,7 @@ void t_rnd() {
             auto p = path_nodes(n, adj, a, b);
             ll sum = 0;
             for (int v : p) sum += val[v];
-            assert(h.qry(a, b) == sum);
+            assert(h.query(a, b) == sum);
         }
     }
 }
diff --git a/tests/3-tree/test_tree_vtree.cpp b/tests/3-tree/test_tree_vtree.cpp
index 44432d3..7266ea1 100644
--- a/tests/3-tree/test_tree_vtree.cpp
+++ b/tests/3-tree/test_tree_vtree.cpp
@@ -85,7 +85,7 @@ void check_one(const vector<vector<int>> &adj, const vector<int> &vs) {
     tc.init(n);
     for (int u = 1; u <= n; u++)
         for (int v : adj[u])
-            if (u < v) tc.add(u, v);
+            if (u < v) tc.add_edge(u, v);
     tc.build(1);
 
     if (vs.empty()) {
diff --git a/tests/3-tree/test_tree_xchg.cpp b/tests/3-tree/test_tree_xchg.cpp
index c325629..cf5ffde 100644
--- a/tests/3-tree/test_tree_xchg.cpp
+++ b/tests/3-tree/test_tree_xchg.cpp
@@ -89,7 +89,7 @@ void check_one(const vector<vector<int>> &adj, int root, const vector<ll> &w, co
     tx.init(n, root);
     for (int u = 1; u <= n; u++)
         for (int v : adj[u])
-            if (u < v) tx.add(u, v);
+            if (u < v) tx.add_edge(u, v);
     for (int i = 1; i <= n; i++) {
         tx.ds.w[i] = w[i];
         tx.ds.t[i] = t[i];