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#pragma once
#include <library/cpp/containers/paged_vector/paged_vector.h>
#include <util/generic/ptr.h>
#include <util/generic/hash.h>
#include <util/generic/vector.h>
#include <util/generic/algorithm.h>
#include <util/memory/pool.h>
namespace NLCS {
template <typename TVal>
struct TLCSCtx {
typedef TVector<ui32> TSubsequence;
typedef THashMap<TVal, TSubsequence, THash<TVal>, TEqualTo<TVal>, ::TPoolAllocator> TEncounterIndex;
typedef TVector<std::pair<ui32, ui32>> TLastIndex;
typedef NPagedVector::TPagedVector<TSubsequence, 4096> TCover;
TMemoryPool Pool;
THolder<TEncounterIndex> Encounters;
TLastIndex LastIndex;
TCover Cover;
TSubsequence ResultBuffer;
TLCSCtx()
: Pool(16 * 1024 - 64, TMemoryPool::TExpGrow::Instance())
{
Reset();
}
void Reset() {
Encounters.Reset(nullptr);
Pool.Clear();
Encounters.Reset(new TEncounterIndex(&Pool));
LastIndex.clear();
Cover.clear();
ResultBuffer.clear();
}
};
namespace NPrivate {
template <typename TIt, typename TVl>
struct TSequence {
typedef TIt TIter;
typedef TVl TVal;
const TIter Begin;
const TIter End;
const size_t Size;
TSequence(TIter beg, TIter end)
: Begin(beg)
, End(end)
, Size(end - beg)
{
}
};
template <typename TVal, typename TSequence, typename TResult>
size_t MakeLCS(TSequence s1, TSequence s2, TResult* res = nullptr, TLCSCtx<TVal>* ctx = nullptr) {
typedef TLCSCtx<TVal> TCtx;
THolder<TCtx> ctxhld;
if (!ctx) {
ctxhld.Reset(new TCtx());
ctx = ctxhld.Get();
} else {
ctx->Reset();
}
size_t maxsize = Max(s1.Size, s2.Size);
auto& index = *(ctx->Encounters);
for (auto it = s1.Begin; it != s1.End; ++it) {
index[*it];
}
for (auto it = s2.Begin; it != s2.End; ++it) {
auto hit = index.find(*it);
if (hit != index.end()) {
hit->second.push_back(it - s2.Begin);
}
}
if (!res) {
auto& lastindex = ctx->ResultBuffer;
lastindex.reserve(maxsize);
for (auto it1 = s1.Begin; it1 != s1.End; ++it1) {
const auto& sub2 = index[*it1];
for (auto it2 = sub2.rbegin(); it2 != sub2.rend(); ++it2) {
ui32 x = *it2;
auto lit = LowerBound(lastindex.begin(), lastindex.end(), x);
if (lit == lastindex.end()) {
lastindex.push_back(x);
} else {
*lit = x;
}
}
}
return lastindex.size();
} else {
auto& lastindex = ctx->LastIndex;
auto& cover = ctx->Cover;
lastindex.reserve(maxsize);
for (auto it1 = s1.Begin; it1 != s1.End; ++it1) {
const auto& sub2 = index[*it1];
for (auto it2 = sub2.rbegin(); it2 != sub2.rend(); ++it2) {
ui32 x = *it2;
auto lit = LowerBound(lastindex.begin(), lastindex.end(), std::make_pair(x, (ui32)0u));
if (lit == lastindex.end()) {
lastindex.push_back(std::make_pair(x, cover.size()));
cover.emplace_back();
cover.back().push_back(x);
} else {
*lit = std::make_pair(x, lit->second);
cover[lit->second].push_back(x);
}
}
}
if (cover.empty()) {
return 0;
}
std::reverse(cover.begin(), cover.end());
auto& resbuf = ctx->ResultBuffer;
resbuf.push_back(cover.front().front());
for (auto it = cover.begin() + 1; it != cover.end(); ++it) {
auto pit = UpperBound(it->begin(), it->end(), resbuf.back(), std::greater<ui32>());
Y_VERIFY(pit != it->end(), " ");
resbuf.push_back(*pit);
}
std::reverse(resbuf.begin(), resbuf.end());
for (auto it = resbuf.begin(); it != resbuf.end(); ++it) {
res->push_back(*(s2.Begin + *it));
}
return lastindex.size();
}
}
}
template <typename TVal, typename TIter, typename TResult>
size_t MakeLCS(TIter beg1, TIter end1, TIter beg2, TIter end2, TResult* res = nullptr, TLCSCtx<TVal>* ctx = nullptr) {
typedef NPrivate::TSequence<TIter, TVal> TSeq;
size_t sz1 = end1 - beg1;
size_t sz2 = end2 - beg2;
if (sz2 > sz1) {
DoSwap(beg1, beg2);
DoSwap(end1, end2);
DoSwap(sz1, sz2);
}
return NPrivate::MakeLCS<TVal>(TSeq(beg1, end1), TSeq(beg2, end2), res, ctx);
}
template <typename TVal, typename TColl, typename TRes>
size_t MakeLCS(const TColl& coll1, const TColl& coll2, TRes* res = nullptr, TLCSCtx<TVal>* ctx = nullptr) {
return MakeLCS<TVal>(coll1.begin(), coll1.end(), coll2.begin(), coll2.end(), res, ctx);
}
template <typename TVal, typename TIter>
size_t MeasureLCS(TIter beg1, TIter end1, TIter beg2, TIter end2, TLCSCtx<TVal>* ctx = nullptr) {
return MakeLCS<TVal>(beg1, end1, beg2, end2, (TVector<TVal>*)nullptr, ctx);
}
template <typename TVal, typename TColl>
size_t MeasureLCS(const TColl& coll1, const TColl& coll2, TLCSCtx<TVal>* ctx = nullptr) {
return MeasureLCS<TVal>(coll1.begin(), coll1.end(), coll2.begin(), coll2.end(), ctx);
}
}
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