diff --git a/string/hash_deque.cc b/string/hash_deque.cc
new file mode 100644
index 0000000..151ba5b
--- /dev/null
+++ b/string/hash_deque.cc
@@ -0,0 +1,54 @@
+static vector<ll> power1, power2;
+template <typename _Tp, typename _Sequence = deque<_Tp>>
+struct hash_deque {
+    using hash_type = pll;
+    static constexpr ll b = 31;
+    static constexpr ll MDL1 = 8784491;
+    static constexpr ll MDL2 = 998244353;
+    static constexpr ll INV1 = 7934379;
+    static constexpr ll INV2 = 128805723;
+    ll hash1, hash2;
+    _Sequence seq;
+    size_t size() {
+        return seq.size();
+    }
+    void push_back(const _Tp& x) {
+        hash1 = mod(mod(hash1 * b, MDL1) + mod(x, MDL1), MDL1);
+        hash2 = mod(mod(hash2 * b, MDL2) + mod(x, MDL2), MDL2);
+        seq.push_back(x);
+    }
+    void push_front(const _Tp& x) {
+        size_t length = size();
+        hash1 = mod(hash1 + mod(mod(x, MDL1) * power1[length], MDL1), MDL1);
+        hash2 = mod(hash2 + mod(mod(x, MDL2) * power2[length], MDL2), MDL2);
+        seq.push_front(x);
+    }
+    void pop_back() {
+        _Tp e = seq.back(); seq.pop_back();
+        hash1 = mod(mod(hash1 - mod(e, MDL1), MDL1) * INV1, MDL1);
+        hash2 = mod(mod(hash2 - mod(e, MDL2), MDL2) * INV2, MDL2);
+    }
+    void pop_front() {
+        _Tp e = seq.front(); seq.pop_front();
+        int length = seq.size();
+        hash1 = mod(hash1 - mod(e * power1[length], MDL1), MDL1);
+        hash2 = mod(hash2 - mod(e * power2[length], MDL2), MDL2);
+    }
+    hash_type hash() {
+        return {hash1, hash2};
+    }
+    void clear() {
+        hash1 = hash2 = 0;
+        seq.clear();
+    }
+    hash_deque(size_t maxn) {
+        clear();
+        int c1 = 1, c2 = 1;
+        for (int i = power1.size(); i < maxn; ++i) {
+            power1.push_back(c1);
+            power2.push_back(c2);
+            c1 = mod(c1 * b, MDL1);
+            c2 = mod(c2 * b, MDL2);
+        }
+    }
+};