diff --git a/include.hh b/include.hh
index 7662cef..8800dff 100644
--- a/include.hh
+++ b/include.hh
@@ -115,6 +115,20 @@ struct pair_hash {
 #define adj(ch, n) __AS_PROCEDURE(vector<vector<int>> ch((n) + 1);)
 #define edge(ch, u, v) __AS_PROCEDURE(ch[u].push_back(v), ch[v].push_back(u);)
 #define Edge(ch, u, v) __AS_PROCEDURE(ch[u].push_back(v);)
+template <typename T, typename Iterator> pair<size_t, map<T, size_t>> discretize(Iterator __first, Iterator __last) {
+    set<T> st(__first, __last);
+    size_t N = 0;
+    map<T, size_t> mp;
+    for (auto&& x : st) mp[x] = ++N;
+    return {N, mp};
+}
+template <typename T, typename Iterator> pair<size_t, unordered_map<T, size_t, safe_hash>> unordered_discretize(Iterator __first, Iterator __last) {
+    set<T> st(__first, __last);
+    size_t N = 0;
+    unordered_map<T, size_t, safe_hash> mp;
+    for (auto&& x : st) mp[x] = ++N;
+    return {N, mp};
+}
 
 /* io */
 #define untie __AS_PROCEDURE(ios_base::sync_with_stdio(0), cin.tie(NULL))