Submission #64101

#	Time	Username	Problem	Language	Result	Execution time	Memory
64101		Bodo171	Min-max tree (BOI18_minmaxtree)	C++14	100 / 100	198 ms	26696 KiB

minmaxtree

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
const int nmax=70005;
vector<int> v[nmax],ad[nmax];
pair<int,int> st[nmax],dr[nmax];
bool viz[nmax];
int l[nmax],r[nmax];
int T[nmax],rg[nmax],low[nmax];
int rmq[20][2*nmax];
int tt[nmax],mark[nmax],first[nmax],lev[nmax];
int n,m,i,j,L,val,a,b,nr,niv,lg[2*nmax],idx;
char ch;
bool changed=0;
struct restr
{
    int value,n1,n2,wh;
};
bool comp(restr unu,restr doi)
{
    return unu.value<doi.value;
}
vector<restr> mins,maxs;
int minlev(int A,int B)
{
    if(lev[A]<lev[B]) return A;
    return B;
}
void build_rmq()
{
    for(i=2;i<=nr;i++)
        lg[i]=lg[i/2]+1;
    for(i=1;(1<<i)<=nr;i++)
        for(j=1;j<=nr-(1<<i)+1;j++)
           rmq[i][j]=minlev(rmq[i-1][j],rmq[i-1][j+(1<<(i-1))]);
}
void dfs(int x)
{
    rmq[0][++nr]=x;first[x]=nr;
    for(int i=0;i<v[x].size();i++)
       if(!tt[v[x][i]])
    {
        lev[v[x][i]]=lev[x]+1;
        tt[v[x][i]]=x;
        dfs(v[x][i]);
        rmq[0][++nr]=x;
    }
}
int lca(int unu,int doi)
{
    unu=first[unu];doi=first[doi];
    if(unu>doi) swap(unu,doi);
    niv=lg[doi-unu+1];
    return minlev(rmq[niv][unu],rmq[niv][doi-(1<<niv)+1]);
}
int finds(int x)
{
    while(x!=T[x])
        x=T[x];
    return x;
}
void unite(int A,int B)
{
    if(A==B) return;
    if(rg[A]>rg[B]) {T[B]=A;rg[A]+=rg[B];low[A]=minlev(low[A],low[B]);}
    else {T[A]=B;rg[B]+=rg[A];low[B]=minlev(low[A],low[B]);}
}
void set_mn(int x,int L)
{
    int prc=0;
    while(x!=-1&&lev[x]>lev[L])
    {
        if(val>st[x].first)
            st[x]={val,idx};
        if(!T[x]) T[x]=x;
        if(T[tt[x]])
            unite(finds(x),finds(tt[x]));
        if(prc)
            unite(finds(prc),finds(x));
        prc=x;
        x=tt[low[finds(x)]];
    }
}
void set_mx(int x,int L)
{
    int prc=0;
    while(x!=-1&&lev[x]>lev[L])
    {
        if(val<dr[x].first)
            dr[x]={val,idx};
        if(!T[x]) T[x]=x;
        if(T[tt[x]])
            unite(finds(x),finds(tt[x]));
        if(prc)
            unite(finds(prc),finds(x));
        prc=x;
        x=tt[low[finds(x)]];
    }
}
bool cup(int x)
{
    if(viz[x]) return 0;
    viz[x]=1;
    for(int i=0;i<ad[x].size();i++)
        if(!r[ad[x][i]])
    {
        l[x]=ad[x][i];
        r[ad[x][i]]=x;
        return 1;
    }
    for(int i=0;i<ad[x].size();i++)
        if(cup(r[ad[x][i]]))
    {
        l[x]=ad[x][i];
        r[ad[x][i]]=x;
        return 1;
    }
    return 0;
}

int main()
{
    //freopen("data.in","r",stdin);
    ios_base::sync_with_stdio(false);
    cin>>n;
    for(i=1;i<=n-1;i++)
    {
        cin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    tt[1]=-1;
    dfs(1);
    for(i=1;i<=n;i++)
       st[i]={-1,0},dr[i]={(1<<30),0};
    build_rmq();
    cin>>m;
    for(i=1;i<=m;i++)
    {
        cin>>ch>>a>>b>>val;
        if(ch=='m') mins.push_back({val,a,b,i});
        else maxs.push_back({val,a,b,i});
    }
    sort(mins.begin(),mins.end(),comp);
    sort(maxs.begin(),maxs.end(),comp);
    for(i=1;i<=n;i++)
        T[i]=0,low[i]=i,rg[i]=1;
    if(mins.size())
       for(i=mins.size()-1;i>=0;i--)
       {
            a=mins[i].n1;b=mins[i].n2;val=mins[i].value;idx=mins[i].wh;
            L=lca(a,b);
            set_mn(a,L);
            set_mn(b,L);
       }
    for(i=1;i<=n;i++)
        T[i]=0,low[i]=i,rg[i]=1;
    for(i=0;i<maxs.size();i++)
    {
        a=maxs[i].n1;b=maxs[i].n2;val=maxs[i].value;idx=maxs[i].wh;
        L=lca(a,b);
        set_mx(a,L);
        set_mx(b,L);
    }
    for(i=1;i<=n;i++)
    {
        if(st[i].second) ad[i].push_back(st[i].second);
        if(dr[i].second) ad[i].push_back(dr[i].second);
    }
    changed=1;
    while(changed)
    {
        changed=0;
        for(i=1;i<=n;i++)
            viz[i]=0;
        for(i=1;i<=n;i++)
            if((!l[i])&&cup(i))
              changed=1;
    }
    for(i=2;i<=n;i++)
    {
        if(!l[i])
        {
            val=1;
            if(st[i].second) val=st[i].first;
            if(dr[i].second) val=dr[i].first;
            cout<<i<<' '<<tt[i]<<' '<<val<<'\n';
        }
        else
        {
            if(l[i]==st[i].second) val=st[i].first;
            else val=dr[i].first;
            cout<<i<<' '<<tt[i]<<' '<<val<<'\n';
        }
    }
    return 0;
}

Compilation message (stderr)

minmaxtree.cpp: In function 'void dfs(int)':
minmaxtree.cpp:42:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<v[x].size();i++)
                 ~^~~~~~~~~~~~
minmaxtree.cpp: In function 'bool cup(int)':
minmaxtree.cpp:106:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<ad[x].size();i++)
                 ~^~~~~~~~~~~~~
minmaxtree.cpp:113:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<ad[x].size();i++)
                 ~^~~~~~~~~~~~~
minmaxtree.cpp: In function 'int main()':
minmaxtree.cpp:160:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<maxs.size();i++)
             ~^~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 22 / 22
• Subtask 3: 29 / 29
• Subtask 4: 42 / 42