Submission #385131

#	Time	Username	Problem	Language	Result	Execution time	Memory
385131		ACmachine	Port Facility (JOI17_port_facility)	C++17	100 / 100	1775 ms	210028 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;

typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;

#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)

const double EPS = 1e-9;
const int MOD = 1e9+7;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};

void DBG(){cout << "]" << endl;}
template<typename T, typename ...U> void DBG(const T& head, const U... args){ cout << head << "; "; DBG(args...); }
#define dbg(...) cout << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__);
#define chk() cout << "Check at line(" << __LINE__ << ") hit." << endl;

template<class T, unsigned int U>
ostream& operator<<(ostream& out, const array<T, U> &v){out << "[";  REP(i, U) out << v[i] << ", ";  out << "]"; return out;}
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}

template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }

const int mod = (int)1e9+7;
struct Mint{
    int val;
    Mint(){ val = 0; }
    Mint(long long v){
        val = (-mod <= v && v < mod) ? v : v%mod;
        if(val < 0) val+= mod;
    }
    // operators
    Mint operator-(){return Mint(-val);}
    Mint& operator+=(const Mint& other){ val+=other.val; if(val >= mod) val-=mod; return *this;}
    Mint& operator-=(const Mint& other){ val-=other.val; if(val < 0) val+=mod; return *this;}
    Mint& operator*=(const Mint& other){ val=((long long)val*other.val)%mod; return *this;}
    friend Mint binpow(Mint a, long long p){
        Mint res(1);
        while(p > 0){
            if(p&1) res*=a; a*=a; p>>=1;
        }
        return res;
    }
    friend Mint inv(Mint a){ return binpow(a, mod-2); }
    Mint& operator/=(const Mint &other){ return (*this)*=inv(other);}

    friend Mint operator+(Mint a, const Mint& b){ return a+=b; }
    friend Mint operator-(Mint a, const Mint& b){ return a-=b; }
    friend Mint operator*(Mint a, const Mint& b){ return a*=b; }
    friend Mint operator/(Mint a, const Mint& b){ return a/=b; }

    bool operator==(const Mint &other){return val == other.val;}
    bool operator!=(const Mint &other){return val != other.val;}
    bool operator<(const Mint &other){return val < other.val;}
    // io
    friend ostream& operator<<(ostream &out, Mint &a){ return out << a.val; }
};
struct bipartite_dsu{
    bool is_bipartite = true;
    vector<array<int, 2>> p;
    vector<set<array<int, 2>>> se;
    vector<int> sz;
    int n;
    vector<int> nb;
    bipartite_dsu(int _n, vector<int> &b) : n(_n), nb(b){
        p.resize(n); sz.resize(n, 1);
        se.resize(n);
        REP(i, n){
            p[i] = {i, 0};
            se[i].insert({0, b[i]});
        }
    }
    array<int, 2> find(int x){
        if(p[x][0] != x){
            int parity = p[x][1];
            p[x] = find(p[x][0]);
            p[x][1] ^= parity;
        }
        return p[x];
    }
    int get_nearest(int component, int parity, int pos){
        auto it = se[component].lower_bound({parity, pos});
        if(it == se[component].end() || (*it)[0] != parity)
            return INF;
        else
            return (*it)[1];
    }
    void join(int u, int v){
        array<int, 2> f = find(u);
        array<int, 2> s = find(v);
        if(f[0] == s[0]){
            if(f[1] == s[1])
                is_bipartite = false;
            return;
        }
        if(sz[f[0]] < sz[s[0]])
            swap(f, s);
        int nparity = f[1] ^ s[1] ^ 1;
        sz[f[0]] += sz[s[0]];
        for(auto x : se[s[0]])
            se[f[0]].insert({x[0]^nparity, x[1]});
        p[s[0]] = {f[0], nparity};
    }
    void join_strong(int u, int v, int begv){
        join(u, v);
        array<int, 2> f = find(u);
        array<int, 2> s = find(v);
        int val = get_nearest(f[0], s[1], begv + 1);
        if(val < nb[v])
            is_bipartite = false;
    }
};

int main(){
 	ios_base::sync_with_stdio(false);
 	cin.tie(NULL); cout.tie(NULL);
    int n; cin >> n;
    vector<int> a(n);
    vector<int> b(n);
    REP(i, n){
        cin >> a[i] >> b[i];
    }
    vector<array<int, 2>> segs(n);
    REP(i, n) segs[i] = {a[i], b[i]};
    sort(all(segs));
    vector<int> nb(n);
    REP(i, n){
        nb[i] = segs[i][1];
    }
    vector<int> rev_b(2 * n + 5, -1);
    REP(i, n){
        rev_b[nb[i]] = i;
    }
    bipartite_dsu d(n, nb);
    set<array<int, 2>> open;
    REP(i, n){
        while(!open.empty() && (*open.begin())[0] < segs[i][0]){
            int comp_id = (*open.begin())[1];
            open.erase(open.begin());
            int nw = min(d.get_nearest(comp_id, 0, segs[i][0]), d.get_nearest(comp_id, 1, segs[i][0]));
            if(nw == INF) continue;
            open.insert({nw, comp_id});
        }
        while(!open.empty() && (*open.begin())[0] < segs[i][1]){
            int b = (*open.begin())[0];
            int rb = rev_b[b];
            open.erase(open.begin());
            d.join_strong(rb, i, segs[i][0]);
        }
        array<int, 2> f = d.find(i);
        int comp_id = f[0];
        int nw = min(d.get_nearest(comp_id, 0, segs[i][0]), d.get_nearest(comp_id, 1, segs[i][0]));
        open.insert({nw, comp_id});
    }
    if(!d.is_bipartite){
        cout << "0\n";
    }
    else{
        Mint ans(1);
        REP(i, n){
            array<int, 2> f = d.find(i);
            if(f[0] == i)
                ans *= Mint(2);
        }
        cout << ans << "\n";
    }
    return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'Mint binpow(Mint, long long int)':
port_facility.cpp:73:13: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   73 |             if(p&1) res*=a; a*=a; p>>=1;
      |             ^~
port_facility.cpp:73:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   73 |             if(p&1) res*=a; a*=a; p>>=1;
      |                             ^

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