Submission #860248

#	Time	Username	Problem	Language	Result	Execution time	Memory
860248		Rafi22	Port Facility (JOI17_port_facility)	C++14	0 / 100	6030 ms	71004 KiB

port_facility

#include <bits/stdc++.h>

#define ll long long
#define ld long double
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
using namespace std;
int inf=1000000007;
ll infl=1000000000000000007;
int mod=1000000007;
int mod1=998244353;

const int N=1000007,pot=1<<21;

pair<int,int> seg[2*pot+7];

pair<int,int> get_mx(int v,int a,int b,int l,int r)
{
    if(a<=l&&b>=r) return seg[v];
    if(r<a||l>b) return {-inf,0};
    return max(get_mx(2*v,a,b,l,(l+r)/2),get_mx(2*v+1,a,b,(l+r)/2+1,r));
}
int ins_mx(int v,int x,int i)
{
    v+=pot-1;
    seg[v]={x,i};
    while(v>1)
    {
        v/=2;
        seg[v]=max(seg[2*v],seg[2*v+1]);
    }
}

pair<int,int> seg1[2*pot+7];

pair<int,int> get_mn(int v,int a,int b,int l,int r)
{
    if(a<=l&&b>=r) return seg1[v];
    if(r<a||l>b) return {inf,0};
    return min(get_mn(2*v,a,b,l,(l+r)/2),get_mn(2*v+1,a,b,(l+r)/2+1,r));
}
int ins_mn(int v,int x,int i)
{
    v+=pot-1;
    seg1[v]={x,i};
    while(v>1)
    {
        v/=2;
        seg1[v]=min(seg1[2*v],seg1[2*v+1]);
    }
}

int l[N],r[N];
int col[N];

int w[2*N];

void dfs(int v)
{
    while(true)
    {
        pair<int,int>p=get_mx(1,l[v],r[v],1,pot);
        if(p.st<=r[v]) break;
        if(col[p.nd]) continue;
        ins_mx(l[p.nd],-inf,p.nd);
        ins_mn(r[p.nd],inf,p.nd);
        col[p.nd]=3-col[v];
        dfs(p.nd);
    }
    while(true)
    {
        pair<int,int>p=get_mn(1,l[v],r[v],1,pot);
        if(p.st>=l[v]) break;
        if(col[p.nd]) continue;
        ins_mx(l[p.nd],-inf,p.nd);
        ins_mn(r[p.nd],inf,p.nd);
        col[p.nd]=3-col[v];
        dfs(p.nd);
    }
}

deque<int>Q[2];

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin>>n;
    for(int i=1;i<=2*pot;i++)
    {
        seg[i].st=-inf;
        seg1[i].st=inf;
    }
    for(int i=1;i<=n;i++)
    {
        cin>>l[i]>>r[i];
        w[l[i]]=i;
        w[r[i]]=-i;
        ins_mx(l[i],r[i],i);
        ins_mn(r[i],l[i],i);
    }
    int cnt=0;
    for(int i=1;i<=n;i++)
    {
        if(col[i]) continue;
        cnt++;
        ins_mx(l[i],-inf,i);
        ins_mn(r[i],inf,i);
        col[i]=1;
        dfs(i);
    }
    for(int i=1;i<=2*n;i++)
    {
        if(w[i]>0) Q[col[w[i]]-1].pb(w[i]);
        else
        {
            w[i]=-w[i];
            if(sz(Q[col[w[i]]-1])==0||Q[col[w[i]]-1].back()!=w[i])
            {
                cout<<0;
                return 0;
            }
            Q[col[w[i]]-1].pop_back();
        }
    }
    int ans=1;
    for(int i=1;i<=cnt;i++) ans=ans*2%mod;
    cout<<ans;

    return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'int ins_mx(int, int, int)':
port_facility.cpp:36:1: warning: no return statement in function returning non-void [-Wreturn-type]
   36 | }
      | ^
port_facility.cpp: In function 'int ins_mn(int, int, int)':
port_facility.cpp:55:1: warning: no return statement in function returning non-void [-Wreturn-type]
   55 | }
      | ^

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22