Submission #234709

#	Time	Username	Problem	Language	Result	Execution time	Memory
234709		Charis02	Port Facility (JOI17_port_facility)	C++14	0 / 100	34 ms	47480 KiB

port_facility

#include<iostream>
#include<stdio.h>
#include<vector>
#include<cmath>
#include<queue>
#include<string.h>
#include<map>
#include<set>
#include<stack>
#include<algorithm>
#define ll long long
#define pi pair < ll,ll >
#define mp(a,b) make_pair(a,b)
#define mid (low+high)/2
#define rep(i,a,b) for(int i = a;i < b;i++)
#define N 2000004
#define INF 1e9+7

using namespace std;

ll n,mod=1e9+7;
pi ar[N];
ll seg[4*N];
bool vis[N];
ll col[N];
ll points[N];
vector < ll > graph[N];

void update(ll low,ll high,ll pos,ll slow,ll val)
{
    if(low==high&&low==slow)
    {
        seg[pos]=val;
        return;
    }
    if(low>slow||high<slow)
        return;
    update(low,mid,pos*2+1,slow,val);
    update(mid+1,high,pos*2+2,slow,val);
    seg[pos]=max(seg[pos*2+1],seg[pos*2+2]);
    return;
}

ll query(ll low,ll high,ll pos,ll slow,ll shigh)
{
    if(low>=slow&&high<=shigh)
        return seg[pos];
    if(low>shigh||high<slow)
        return 0;
    return max(query(low,mid,pos*2+1,slow,shigh),query(mid+1,high,pos*2+2,slow,shigh));
}

void dfs(ll cur,ll c)
{
    if(vis[cur])
        return;
    col[cur] = c;
    vis[cur]=true;

    rep(i,0,graph[cur].size())
        dfs(graph[cur][i],!c);
    return;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    cin >> n;

    rep(i,0,n)
    {
        cin >> ar[i].first >> ar[i].second;
    }

    sort(ar,ar+n);

    rep(i,0,n)
    {
        points[ar[i].first]=i;
        points[ar[i].second]=i;
        ll q = query(0,2*n,0,ar[i].first,ar[i].second);
        if(q!=0)
        {
            q--;
            graph[q].push_back(i);
            graph[q].push_back(q);
        }
        update(0,2*n,0,ar[i].second,i+1);
    }

    ll ans = 1;
    rep(i,0,n)
    {
        if(!vis[i])
            ans=(ans*2)%mod;
        dfs(i,0);
    }

    stack < ll > s[2];

    rep(i,1,2*n+1)
    {
        ll ind = points[i];
        if(ar[ind].first==i)
        {
            s[col[ind]].push(ind);
        }
        else
        {
            if(s[col[ind]].top() != ind)
            {
                ans=0;
                break;
            }
            else
                s[col[ind]].pop();
        }
    }

    cout << ans << endl;

    return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'void dfs(long long int, long long int)':
port_facility.cpp:15:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define rep(i,a,b) for(int i = a;i < b;i++)
port_facility.cpp:60:9:
     rep(i,0,graph[cur].size())
         ~~~~~~~~~~~~~~~~~~~~~       
port_facility.cpp:60:5: note: in expansion of macro 'rep'
     rep(i,0,graph[cur].size())
     ^~~

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