Submission #185354

#	Time	Username	Problem	Language	Result	Execution time	Memory
185354		nicolaalexandra	Railway (BOI17_railway)	C++14	100 / 100	758 ms	131944 KiB

railway

#include <bits/stdc++.h>
#define DIM 1000010
using namespace std;
int whatChain[DIM],positionInChain[DIM],chainFatherNode[DIM],Size[DIM],level[DIM];
int viz[DIM],low[DIM],niv[DIM],b[DIM],E[DIM*3],first[DIM],fth[DIM],p[DIM],v[DIM];
pair <int,int> rmq[20][DIM*3];
map <pair<int,int>,int> mch;
vector <int> chains[DIM],L[DIM],sol;
vector <pair<int,int> > a[DIM];
int n,m,k,i,j,nod,nr_chains,x,y,nr,lca,aux,K;
void dfs (int nod, int tata){
    E[++k] = nod;
    first[nod] = k;
    niv[nod] = 1 + niv[tata];
    fth[nod] = tata;
    for (auto vecin:L[nod]){
        if (vecin != tata){
            dfs (vecin,nod);
            E[++k] = nod;
        }}
}
void pre_dfs (int nod, int tata){
    viz[nod] = Size[nod] = 1;
    level[nod] = 1+level[tata];
    int ok = 0;
    for (int i=0;i<L[nod].size();i++){
        int vecin = L[nod][i];
        if (!viz[vecin]){
            ok = 1;
            pre_dfs (vecin,nod);
            Size[nod] += Size[vecin]; /// cate noduri am in subarbore
        }}
    if (!ok){ /// inseamna ca e frunza deci incep un nou lant
        nr_chains++;
        chains[nr_chains].push_back(0); /// le vreau indexate de la 1
        chains[nr_chains].push_back(nod);
        whatChain[nod] = nr_chains; /// pe ce lant se afla x
        positionInChain[nod] = 1; /// pozitia in lant
    } else {
        /// pun nodul curent la capatul lantului fiului cel mai "greu", adica cel care Size ul maxim
        int maxim = 0, poz = 0;
        for (int i=0;i<L[nod].size();i++){
            int fiu = L[nod][i];
            if (fiu == tata)
                continue;
            if (Size[fiu] > maxim){
                maxim = Size[fiu];
                poz = fiu;
            }}
        /// acum il atasez la fiu
        chains[whatChain[poz]].push_back(nod);
        whatChain[nod] = whatChain[poz];
        positionInChain[nod] = chains[whatChain[poz]].size()-1;
        /// acum calculez chain father node
        for (int i=0;i<L[nod].size();i++){
            int fiu = L[nod][i];
            if (fiu == tata)
                continue;
            if (fiu != poz)
                chainFatherNode[whatChain[fiu]] = nod;
        }}}

void update_lazy (int chain, int nod, int st, int dr){
    a[chain][nod].first += (dr-st+1)*a[chain][nod].second;
    if (st != dr){
        a[chain][2*nod].second += a[chain][nod].second;
        a[chain][2*nod+1].second += a[chain][nod].second;
    }
    a[chain][nod].second = 0;
    return;
}
void update_aint (int chain, int nod, int st, int dr, int x, int y, int val){
    update_lazy(chain,nod,st,dr);
    if (st > dr || x > y || x > dr || y < st)
        return;
    if (x <= st && dr <= y){
        a[chain][nod].second += val;
        update_lazy (chain,nod,st,dr);
        return;
    }
    int mid = (st+dr)/2;
    update_aint(chain,2*nod,st,mid,x,y,val);
    update_aint(chain,2*nod+1,mid+1,dr,x,y,val);
    a[chain][nod].first = a[chain][2*nod].first + a[chain][2*nod+1].first;
    return;
}
int query_aint (int chain, int nod, int st, int dr, int poz){
    update_lazy(chain,nod,st,dr);
    if (st == dr)
        return a[chain][nod].first;

    int mid = (st+dr)>>1;
    if (poz <= mid)
        query_aint (chain,nod<<1,st,mid,poz);
    else query_aint (chain,(nod<<1)|1,mid+1,dr,poz);
}
void update_heavy (int x, int y, int val){
    if (whatChain[x] == whatChain[y]){
        int posx = positionInChain[x], posy = positionInChain[y];
        if (posx > posy)
            swap (posx,posy);
        if (x == nod)
            posx++;
        if (y == nod)
            posy--;
        if (posx > posy)
            return;
        update_aint (whatChain[x],1,1,chains[whatChain[x]].size()-1,posx,posy,val);
        return;
    }

    if (level[chainFatherNode[whatChain[x]]] <= level[chainFatherNode[whatChain[y]]])
        swap (x,y);


    int poz_st = positionInChain[x], poz_dr = chains[whatChain[x]].size()-1;
    if (chains[whatChain[x]][poz_st] == nod)
        poz_st++;
    if (chains[whatChain[x]][poz_dr] == nod)
        poz_dr--;
    if (poz_st <= poz_dr)
        update_aint (whatChain[x],1,1,chains[whatChain[x]].size()-1,poz_st,poz_dr,val);
    int nr = chainFatherNode[whatChain[x]];
    update_heavy (nr,y,val);
}

int get_lca (int x, int y){
    int pozx = first[x], pozy = first[y];
    if (pozx > pozy)
        swap (pozx,pozy);
    int nr = p[pozy-pozx+1];
    pair <int,int> sol = min (rmq[nr][pozx],rmq[nr][pozy-(1<<nr)+1]);
    return E[sol.second];
}
inline int cmp (int a, int b){
    return first[a] < first[b];
}
int main (){
    //ifstream cin ("date.in");
    //ofstream cout ("date.out");

    cin>>n>>m>>K;
    for (i=1;i<n;i++){
        cin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
        mch[make_pair(x,y)] = i;
        mch[make_pair(y,x)] = i;
    }

    dfs (1,0);

    for (i=1;i<=k;i++)
        rmq[0][i] = make_pair(niv[E[i]],i);

    for (i=1;(1<<i)<=k;i++)
        for (j=1;j<=k;j++){
            rmq[i][j] = rmq[i-1][j];
            if (j+(1<<(i-1)) <= k && rmq[i-1][j+(1<<(i-1))].first < rmq[i][j].first)
                rmq[i][j] = rmq[i-1][j+(1<<(i-1))];
        }

    for (i=2;i<=k;i++)
        p[i] = p[i/2]+1;

    /// heavy
    pre_dfs(1,0);
    for (i=1;i<=nr_chains;i++){
        for (int j=0;j<2*chains[i].size();j++)
            a[i].push_back(make_pair(0,0));
    }

    for (i=1;i<=m;i++){
        cin>>nr;
        for (j=1;j<=nr;j++)
            cin>>v[j];
        /// determin lca-ul tuturor
        int lca = get_lca (v[1],v[2]);
        for (j=3;j<=nr;j++)
            lca = get_lca (lca,v[j]);
        v[++nr] = lca;
        sort (v+1,v+nr+1,cmp);
        /// elimin dublurile
        int nr2 = 1;
        for (j=2;j<=nr;j++)
            v[++nr2] = v[j];
        nr = nr2;

        aux = v[1];
        for (j=2;j<=nr;j++){

            lca = get_lca (aux,v[j]);
            /// fac update pe lantul lca...v[j], dar nu trb sa fac si in lca
            nod = lca;
            update_heavy(v[j],lca,1);

            aux = v[j];
        }

        /*s.clear();
        s.push_back(v[1]);
        for (i=2;i<=n;i++){
            /// elimin din stiva cat timp nu e un stramos
            while (!s.empty() && verif(v[s.back()],v[i]))
                s.pop_back();
            x = v[s.back()], y = v[i];
            /// trb sa fac update pe lantul asta, dar sa nu fac update in x!!
            nod = x;
            update_heavy (x,y,1);
        }*/

    }
    for (i=2;i<=n;i++){
        int val = query_aint (whatChain[i],1,1,chains[whatChain[i]].size()-1,positionInChain[i]);
        if (val >= K)
            sol.push_back(mch[make_pair(i,fth[i])]);
    }

    sort (sol.begin(),sol.end());
    cout<<sol.size()<<"\n";
    for (auto it:sol)
        cout<<it<<" ";


    return 0;
}

Compilation message (stderr)

railway.cpp: In function 'void pre_dfs(int, int)':
railway.cpp:26:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0;i<L[nod].size();i++){
                  ~^~~~~~~~~~~~~~
railway.cpp:42:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i=0;i<L[nod].size();i++){
                      ~^~~~~~~~~~~~~~
railway.cpp:55:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i=0;i<L[nod].size();i++){
                      ~^~~~~~~~~~~~~~
railway.cpp: In function 'int main()':
railway.cpp:169:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j=0;j<2*chains[i].size();j++)
                      ~^~~~~~~~~~~~~~~~~~~
railway.cpp: In function 'int query_aint(int, int, int, int, int)':
railway.cpp:96:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25