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Create hash_deque.cc

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Ariel 2024-02-18 13:07:29 +08:00 committed by GitHub
parent 4920d0b1f0
commit d4e5d2a21c
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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);
}
}
};