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#include "gd_builder.h"

#include <library/cpp/string_utils/relaxed_escaper/relaxed_escaper.h>
#include <util/generic/algorithm.h>

#include <util/random/shuffle.h>
#include <util/stream/output.h>
#include <util/string/printf.h>
#include <util/system/rusage.h>

namespace NGreedyDict {
    void TDictBuilder::RebuildCounts(ui32 maxcand, bool final) { 
        if (!Current) { 
            Current = MakeHolder<TEntrySet>();
            Current->InitWithAlpha(); 
        } 

        TEntrySet& set = *Current; 

        for (auto& it : set) 
            it.Count = 0; 

        CompoundCounts = nullptr; 
        CompoundCountsPool.Clear(); 

        if (!final) { 
            CompoundCounts = MakeHolder<TCompoundCounts>(&CompoundCountsPool);
            CompoundCounts->reserve(maxcand); 
        } 

        Shuffle(Input.begin(), Input.end(), Rng); 

        for (auto str : Input) { 
            if (!final && CompoundCounts->size() > maxcand) 
                break; 

            i32 prev = -1; 

            while (!!str) { 
                TEntry* e = set.FindPrefix(str); 
                ui32 num = e->Number; 

                e->Count += 1; 
                if (!final && prev >= 0) { 
                    (*CompoundCounts)[Compose(prev, num)] += 1; 
                } 

                prev = num; 
                ++set.TotalCount; 
            }
        } 

        Current->SetModelP(); 
    }

    ui32 TDictBuilder::BuildNextGeneration(ui32 maxent) { 
        TAutoPtr<TEntrySet> newset = new TEntrySet; 
        newset->InitWithAlpha(); 
        maxent -= newset->size(); 

        ui32 additions = 0; 
        ui32 deletions = 0; 

        { 
            const TEntrySet& set = *Current; 

            Candidates.clear(); 
            const ui32 total = set.TotalCount; 
            const float minpval = Settings.MinPValue; 
            const EEntryStatTest test = Settings.StatTest; 
            const EEntryScore score = Settings.Score; 
            const ui32 mincnt = Settings.MinAbsCount; 

            for (const auto& it : set) { 
                const TEntry& e = it; 
                float modelp = e.ModelP; 
                ui32 cnt = e.Count; 

                if (e.HasPrefix() && e.Count > mincnt && StatTest(test, modelp, cnt, total) > minpval) 
                    Candidates.push_back(TCandidate(-Score(score, e.Len(), modelp, cnt, total), it.Number)); 
            } 

            if (!!CompoundCounts) { 
                for (TCompoundCounts::const_iterator it = CompoundCounts->begin(); it != CompoundCounts->end(); ++it) { 
                    const TEntry& prev = set.Get(Prev(it->first)); 
                    const TEntry& next = set.Get(Next(it->first)); 
                    float modelp = ModelP(prev.Count, next.Count, total); 
                    ui32 cnt = it->second; 
                    if (cnt > mincnt && StatTest(test, modelp, cnt, total) > minpval) 
                        Candidates.push_back(TCandidate(-Score(score, prev.Len() + next.Len(), modelp, cnt, total), it->first)); 
                } 
            }

            Sort(Candidates.begin(), Candidates.end()); 

            if (Candidates.size() > maxent) 
                Candidates.resize(maxent); 

            for (const auto& candidate : Candidates) { 
                if (IsCompound(candidate.second)) { 
                    additions++; 
                    newset->Add(set.Get(Prev(candidate.second)).Str, set.Get(Next(candidate.second)).Str); 
                } else { 
                    newset->Add(set.Get(candidate.second).Str); 
                } 
            }
 
            deletions = set.size() - (newset->size() - additions); 
        }

        Current = newset; 
        Current->BuildHierarchy(); 
        return deletions + additions; 
    }

    ui32 TDictBuilder::Build(ui32 maxentries, ui32 maxiters, ui32 mindiff) { 
        size_t totalsz = 0; 
        for (auto it : Input) 
            totalsz += it.size();

        while (maxiters) { 
            maxiters--; 

            RebuildCounts(maxentries * Settings.GrowLimit, false); 

            if (Settings.Verbose) { 
                TString mess = Sprintf("iter:%" PRIu32 " sz:%" PRIu32 " pend:%" PRIu32, maxiters, (ui32)Current->size(), (ui32)CompoundCounts->size()); 
                Clog << Sprintf("%-110s RSS=%" PRIu32 "M", mess.data(), (ui32)(TRusage::Get().MaxRss >> 20)) << Endl;
            } 

            ui32 diff = BuildNextGeneration(maxentries); 
 
            if (Current->size() == maxentries && diff < mindiff) 
                break; 
        }

        RebuildCounts(0, true); 
        Current->SetScores(Settings.Score); 
        return maxiters; 
    }

}