Submission #1086815

#	Time	Username	Problem	Language	Result	Execution time	Memory
1086815		steveonalex	Port Facility (JOI17_port_facility)	C++17	100 / 100	1325 ms	152272 KiB

port_facility

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
#define block_of_code if(true)
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

struct DSU{
    int n;
    vector<pair<int, int>> parent;
    vector<int> sz;
    vector<int> ma;
    bool bipartite = true;


    DSU(int _n){
        n = _n;
        parent.resize(n+1); sz.resize(n+1, 1);
        ma.resize(n+1);
        for(int i = 1; i<=n; ++i) parent[i] = {i, 0};
    }

    pair<int, int> find_set(int u){
        if (u == parent[u].first) return make_pair(u, 0);
        pair<int, int> v = find_set(parent[u].first);
        v.second ^= parent[u].second;
        return parent[u] = v;
    }
    bool same_set(int u, int v){return find_set(u) == find_set(v);}

    bool join_set(int u, int v, int w = 1){
        pair<int, int> x = find_set(u), y = find_set(v);
        u = x.first, v = y.first;
        w ^= x.second ^ y.second;
        if (u != v){
            if (sz[u] < sz[v]) swap(u, v);
            parent[v] = {u, w};
            sz[u] += sz[v];
            maximize(ma[u], ma[v]);
            return true;
        }
        if (w == 1) bipartite = false;
        return false;
    }

    int get_size(int u){return sz[find_set(u).first];}

    int get_ma(int u){return ma[find_set(u).first];}
    void set_ma(int u, int x){
        maximize(ma[find_set(u).first], x);
    }
};
 
int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    clock_t start = clock();
 
    int n; cin >> n;
    vector<pair<int,int>> a(n);
    for(int i= 0; i<n; ++i) cin >> a[i].first >> a[i].second;

    vector<int> from_left(n*2+1, -1), from_right(n*2+1, -1);
    for(int i= 0; i<n; ++i) {
        from_left[a[i].first] = from_right[a[i].second] = i;
    }

    set<int> S;
    int cc = n;
    DSU mst(n);

    for(int i = 1; i<=n*2; ++i){
        int j = from_left[i];
        if (j == -1) continue;
        mst.set_ma(j, i);
        while(true){
            auto it = S.upper_bound(mst.get_ma(j));
            if (it == S.end() || *it >= a[j].second) break;
            int k = from_right[*it];
            cc -= mst.join_set(j, k);
        }
        mst.set_ma(j, a[j].second);
        S.insert(a[j].second);
    }

    vector<int> color(n);
    for(int i = 0; i<n; ++i) 
        color[i] = mst.find_set(i).second;

    set<int> odd, even;
    bool bipartite = true;
    for(int i= 1; i<=n*2; ++i){
        int j = from_left[i];
        if (j == -1) continue;

        if (color[j]) swap(odd, even); 

        auto it = even.upper_bound(i);
        if (it != even.end() && *it <= a[j].second) {
            bipartite = false;
        }

        if (color[j]) swap(odd, even);

        if (color[j]) odd.insert(a[j].second);
        else even.insert(a[j].second);
    }

    if (!bipartite){
        cout << 0 << "\n";
        exit(0);
    }


    const int MOD = 1e9 + 7;
    int ans = 1;
    while(cc--){
        ans *= 2;
        if (ans >= MOD) ans -= MOD;
    }
    cout << ans << "\n";

 
    cerr << "Time elapsed: " << clock() - start << " ms\n";
    return 0;
}

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