Submission #367500

#	Time	Username	Problem	Language	Result	Execution time	Memory
367500		balbit	Port Facility (JOI17_port_facility)	C++14	100 / 100	1207 ms	172776 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define y1 zck_is_king
#define pii pair<int, int>
#define ull unsigned ll
#define f first
#define s second
#define ALL(x) x.begin(),x.end()
#define SZ(x) (int)x.size()
#define SQ(x) (x)*(x)
#define MN(a,b) a = min(a,(__typeof__(a))(b))
#define MX(a,b) a = max(a,(__typeof__(a))(b))
#define pb push_back
#define REP(i,n) for (int i = 0; i<n; ++i)
#define RREP(i,n) for (int i = n-1; i>=0; --i)
#define REP1(i,n) for (int i = 1; i<=n; ++i)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#ifdef BALBIT
#define IOS()
#define bug(...) fprintf(stderr,"#%d (%s) = ",__LINE__,#__VA_ARGS__),_do(__VA_ARGS__);
template<typename T> void _do(T &&x){cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T &&x, S &&...y){cerr<<x<<", ";_do(y...);}
#else
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0);
#define endl '\n'
#define bug(...)
#endif

const int iinf = 1e9+10;
const ll inf = 1ll<<60;
const ll mod = 1e9+7 ;


void GG(){cout<<"0\n"; exit(0);}

ll mpow(ll a, ll n, ll mo = mod){ // a^n % mod
    ll re=1;
    while (n>0){
        if (n&1) re = re*a %mo;
        a = a*a %mo;
        n>>=1;
    }
    return re;
}

ll inv (ll b, ll mo = mod){
    if (b==1) return b;
    return (mo-mo/b) * inv(mo%b,mo) % mo;
}

const int maxn = 2e6+5;

int par[maxn];
int find(int x) {return x==par[x]?x:par[x] = find(par[x]);}

int cc = 0;

vector<int> g[maxn];

void mg(int a, int b) {
    int A=find(a), B=find(b);
    if (A!=B) {
        --cc;
        par[A] = B;
        g[a].pb(b); g[b].pb(a);
        bug(a,b);
    }
}

int col[maxn];

void dfs(int v) {
    for (int u : g[v]) {
        if (col[u] == -1) {
            col[u] = col[v] ^ 1;
            dfs(u);
        }
    }
}

struct seg{
    int l,r,i;
};

int who[maxn];
bool pluck[maxn];

signed main(){
    IOS();
    memset(col, -1, sizeof col);
    int n; cin>>n;
    REP(i,n) par[i] = i;
    vector<seg> v;
    cc = n;

    REP(i,n) {
        int a,b; cin>>a>>b;
        v.pb({a,b,i});
        who[a]=who[b]=i; pluck[b] = 1;
    }
    REP(hi,2) {
        vector<seg>q;
        sort(ALL(v), [&](seg a, seg b){return a.r < b.r;});
        REP(i,n) {
            while (!q.empty() && q.back().l > v[i].l) q.pop_back();
            if (!q.empty() && q.back().r > v[i].l) {
                mg(v[i].i, q.back().i);
//                if (q.back().i==0 && v[i].i==2) {
//                    bug(q.back().r, v[i].l);
//                }
//                q.back().r = v[i].r; q.back().
//            }else{
            }
            q.pb(v[i]);

        }
//        bug("HO");
        for (seg & s : v) {
            s.l=-s.l; s.r=-s.r;
            swap(s.l, s.r);
        }
    }
    bug(cc);
    REP(i,n) {
        if (col[i] == -1) {
            col[i] = 0; dfs(i);
        }
    }
    REP(i,n) bug(i, col[i]);
    vector<int> s1,s2; s1.pb(-1); s2.pb(-1);
    REP1(i,2*n){
        if (pluck[i]) {
            if (s1.back()==who[i]) s1.pop_back();
            else if (s2.back()==who[i]) s2.pop_back();
            else GG();
        }else{
            (col[who[i]]?s1:s2).pb(who[i]);
        }
    }

    cout<<mpow(2,cc)<<endl;

}

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