Submission #1100823

#	Time	Username	Problem	Language	Result	Execution time	Memory
1100823		vivkostov	Joker (BOI20_joker)	C++14	14 / 100	2073 ms	8660 KiB

Joker

#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}
struct cell
{
    int a,b,tim;
};
int n,m,q,a[200005],b[200005],l,r,lead[200005],sw[200005],sz[200005],lamp,otg[200005],br;
stack<cell>s;
void prec()
{
    for(int i=1;i<=n;i++)
    {
        lead[i]=i;
        sz[i]=1;
        sw[i]=0;
    }
}
int get_lead(int beg)
{
    if(lead[beg]==beg)return beg;
    return get_lead(lead[beg]);
}
int get_br(int beg,int br)
{
    if(lead[beg]==beg)return br;
    return get_br(lead[beg],br+sw[beg]);
}
void add(int a,int b)
{
    br++;
    int la=get_lead(a);
    int lb=get_lead(b);
    if(la==lb)
    {
        if(get_br(a,0)%2==get_br(b,0)%2)lamp=br;
        return;
    }
    if(sz[la]<sz[lb])
    {
        swap(la,lb);
        swap(a,b);
    }
    lead[lb]=la;
    sz[la]+=sz[lb];
    if(get_br(a,0)%2==get_br(b,0)%2)sw[lb]++;
    cell h;
    h.a=la;
    h.b=lb;
    h.tim=br;
    s.push(h);
}
void rem(int num)
{
    for(int i=1;i<=num;i++)
    {
        if(s.top().tim==br)
        {
            int a=s.top().a;
            int b=s.top().b;
            s.pop();
            sz[a]-=sz[b];
            lead[b]=b;
        }
        br--;
        if(br<lamp)lamp=0;
    }
}
void rec(int l1,int l2,int r1,int r2)
{
    if(l1>l2)return;
    int mid=(l1+l2)/2;
    int nbr=br;
    for(int i=l1;i<mid;i++)
    {
        add(a[i],b[i]);
    }
    //cout<<br<<endl;
    int x=r2;
    int obr=br;
    while(!lamp&&x>max(mid,r1))
    {
        x--;
        add(a[x],b[x]);
    }
    int ubr=br;
    otg[mid]=x;
    //cout<<l1<<" "<<l2<<" "<<r1<<" "<<r2<<" "<<otg[mid]<<endl;
    //cout<<nbr<<" "<<obr<<" "<<br<<" "<<mid<<endl;
    rem(ubr-obr);

    add(a[mid],b[mid]);

    rec(mid+1,l2,otg[mid],r2);

    rem(mid-l1+1);

    //cout<<l1<<" "<<l2<<" "<<br<<" "<<nbr<<" "<<obr<<" "<<ubr<<" "<<otg[mid]<<endl;

    for(int i=r2-1;i>=otg[mid];i--)
    {
        add(a[i],b[i]);
    }

    rec(l1,mid-1,r1,otg[mid]);

    rem(r2-otg[mid]);
}
void read()
{
    cin>>n>>m>>q;
    prec();
    for(int i=1;i<=m;i++)
    {
        cin>>a[i]>>b[i];
    }
    //rec(1,m,1,m+1);
    for(int i=1;i<=q;i++)
    {
        cin>>l>>r;
        for(int i=1;i<l;i++)
        {
            add(a[i],b[i]);
        }
        for(int i=r+1;i<=m;i++)
        {
            add(a[i],b[i]);
        }
        if(lamp)cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
        rem(l-1);
        rem(m-r);
        //if(otg[l]>r)cout<<"YES"<<endl;
        //else cout<<"NO"<<endl;
    }
}
int main()
{
    speed();
    read();
    return 0;
}

Compilation message (stderr)

Joker.cpp: In function 'void rec(int, int, int, int)':
Joker.cpp:79:9: warning: unused variable 'nbr' [-Wunused-variable]
   79 |     int nbr=br;
      |         ^~~

• Subtask 1: 6 / 6
• Subtask 2: 8 / 8
• Subtask 3: 0 / 25
• Subtask 4: 0 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29