1
0
Fork 0
cp-templates/string/hash_vec.cc

92 lines
2.5 KiB
C++
Raw Normal View History

static vector<MLL<MDL1>> power1;
static vector<MLL<MDL2>> power2;
static const ll b = rd();
template <typename _Tp>
struct hash_vec {
using hash_type = pll;
MLL<MDL1> hash1;
MLL<MDL2> hash2;
vector<_Tp> seq;
size_t size() {
return seq.size();
}
void push_back(const _Tp& x) {
hash1 = hash1 * b + x;
hash2 = hash2 * b + x;
seq.push_back(x);
}
void push_front(const _Tp& x) {
size_t length = size();
hash1 += x * power1[length];
hash2 += x * power2[length];
seq.push_front(x);
}
void pop_back() {
_Tp e = seq.back(); seq.pop_back();
hash1 = (hash1 - e) / b;
hash2 = (hash2 - e) / b;
}
void pop_front() {
_Tp e = seq.front(); seq.pop_front();
int length = seq.size();
hash1 -= e * power1[length];
hash2 -= e * power2[length];
}
void set(size_t pos, const _Tp& value) {
int length = seq.size();
int old_value = seq[pos];
hash1 += (value - old_value) * power1[length - 1 - pos];
hash2 += (value - old_value) * power2[length - 1 - pos];
seq[pos] = value;
}
const _Tp& operator[](size_t pos) {
return seq[pos];
}
hash_type hash() {
return {hash1.val, hash2.val};
}
void clear() {
hash1 = 0;
hash2 = 0;
seq.clear();
}
hash_vec(size_t maxn) {
clear();
MLL<MDL1> c1 = power1.size() ? power1.back() * b : 1;
MLL<MDL2> c2 = power2.size() ? power2.back() * b : 1;
for (int i = power1.size(); i < maxn; ++i) {
power1.push_back(c1);
power2.push_back(c2);
c1 *= b;
c2 *= b;
}
}
hash_vec(size_t maxn, const _Tp& init_value) : hash_vec(maxn) {
for (size_t i = 0; i != maxn; ++i) {
push_back(init_value);
}
}
};
struct range_hash {
vector<pair<MLL<MDL1>, MLL<MDL2>>> hp;
template <typename T>
range_hash(const T& vec) {
hp.emplace_back();
hash_vec<ll> hs(vec.size());
for (auto&& x : vec) {
hs.push_back(x);
hp.emplace_back(hs.hash());
}
}
/// query hash of subarray [l, r]. Index starts from 0.
pair<MLL<MDL1>, MLL<MDL2>> range_query(size_t l, size_t r) {
return {
(hp[r + 1].first - hp[l].first * power1[r + 1 - l]),
(hp[r + 1].second - hp[l].second * power2[r + 1 - l]),
};
}
};