diff --git a/trees/segtree_dac.cc b/trees/segtree_dac.cc
new file mode 100644
index 0000000..3ae8bbc
--- /dev/null
+++ b/trees/segtree_dac.cc
@@ -0,0 +1,66 @@
+template<typename Addable_Info_t, typename Tag_t, typename Sequence = std::vector<Addable_Info_t>> class segtree {
+private:
+    using size_type = uint64_t;
+    using info_type = Addable_Info_t;
+    using tag_type = Tag_t;
+    size_type _max;
+    vector<info_type> d;
+    vector<tag_type> b;
+
+    void range_apply(size_type s, size_type t, size_type p, size_type l, size_type r, const tag_type& c) {
+        if (l <= s && t <= r) {
+            d[p].apply(c, t - s + 1);
+            return;
+        }
+        size_type m = s + (t - s >> 1);
+        if (l <= m) range_apply(s, m, p * 2, l, r, c);
+        if (r > m)  range_apply(m + 1, t, p * 2 + 1, l, r, c);
+    }
+    void range_query(size_type s, size_type t, size_type p, size_type l, size_type r) {
+        int cnt = 0;
+        for (auto&& [u, v] : d[p].ops) {
+            qu.merge(u, v);
+            ++cnt;
+        }
+        if (s == t) {
+            auto&& [v, idx] = queries[s];
+            if (v != -1) {
+                res[idx] = qu.query_size(v);
+            }
+        } else {
+            size_type m = s + (t - s >> 1);
+            if (l <= m) range_query(s, m, p * 2, l, r);
+            if (r > m)  range_query(m + 1, t, p * 2 + 1, l, r);
+        }
+        while (cnt--) {
+            qu.rollback();
+        }
+    }
+public:
+    segtree(size_type __max) : d(4 * __max), b(4 * __max), _max(__max - 1) {}
+
+    void range_apply(size_type l, size_type r, const tag_type& c) {
+        range_apply({}, _max, 1, l, r, c);
+    }
+    void range_query(size_type l, size_type r) {
+        return range_query({}, _max, 1, l, r);
+    }
+    const vector<info_type>& get_d() {
+        return d;
+    }
+};
+struct Tag {
+    int u = -1, v = -1;
+    void apply(const Tag& rhs) {
+    }
+};
+struct Info {
+    vector<pii> ops;
+    void apply(const Tag& rhs, size_t len) {
+        if (rhs.u == -1 and rhs.v == -1) return;
+        ops.emplace_back(rhs.u, rhs.v);
+    }
+};
+Info operator+(const Info &a, const Info &b) {
+    return {};
+}