Submission #447758

#	Time	Username	Problem	Language	Result	Execution time	Memory
447758		Haruto810198	Port Facility (JOI17_port_facility)	C++17	0 / 100	14 ms	23764 KiB

port_facility

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define double long double

#define FOR(i,l,r,d) for(int i=(l);i<=(r);i+=(d))
#define szof(x) ((int)(x).size())

#define vi vector<int>
#define pii pair<int,int>

#define F first
#define S second

#define pb push_back
#define eb emplace_back
#define mkp make_pair

const int INF = 2147483647;
const int LNF = INF*INF;
const int MOD = 1000000007;
const int mod = 998244353;
const double eps = 1e-12;

//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")

const int MAX = 1000010;

int n;
int in[MAX], out[MAX];
int op[2*MAX];

bool popped[MAX];
vi edge[MAX];

vi qu;

int pa[MAX];
int dep[MAX];

int CCs;

int vis[MAX];
int tag[MAX];
int res = 1;

int qu_pos[MAX];
int nxt[MAX];

int findp(int v){
    if(v == pa[v]) return v;
    return (pa[v] = findp(pa[v]));
}

void uni(int u, int v){

    int pu = findp(u);
    int pv = findp(v);

    if(pu != pv){
        CCs--;
        if(dep[pu] < dep[pv]){
            swap(pu, pv);
        }
        if(dep[pu] == dep[pv]){
            dep[pu]++;
        }
        pa[pv] = pu;
    }

}

void dfs(int v){
    for(int i : edge[v]){
        if(vis[i] == 0){
            vis[i] = 1;
            tag[i] = 1 - tag[v];
            dfs(i);
        }
        else{
            if(tag[v] + tag[i] != 1){
                res = 0;
            }
        }
    }
}

signed main(){

    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    cin>>n;
    FOR(i, 1, n, 1){
        cin>>in[i]>>out[i];
        op[in[i]] = i;
        op[out[i]] = -i;
    }

    FOR(i, 0, n, 1){
        pa[i] = i;
        dep[i] = 0;
        tag[i] = -1;
        nxt[i] = i+1;
    }
    CCs = n;

    FOR(i, 1, 2*n, 1){

        if(op[i] > 0){
            qu.pb(op[i]);
            qu_pos[op[i]] = szof(qu) - 1;
        }
        else if(op[i] < 0){

            popped[-op[i]] = 1;

            FOR(j, qu_pos[-op[i]] + 1, szof(qu) - 1, 0){

                int tmp = nxt[j];
                nxt[j] = max(nxt[j], szof(qu) - 1);

                if(popped[qu[j]] == 0){
                    edge[qu[j]].pb(-op[i]);
                    edge[-op[i]].pb(qu[j]);
                    uni(qu[j], -op[i]);
                }

                j = tmp;

            }

        }

    }

    /*
    FOR(i, 1, n, 1){
        cerr<<"edge["<<i<<"] : ";
        for(int j : edge[i]){
            cerr<<j<<" ";
        }
        cerr<<endl;
    }
    */

    FOR(i, 1, n, 1){
        if(vis[i] == 0){
            vis[i] = 1;
            tag[i] = 0;
            dfs(i);
        }
    }

    FOR(i, 1, CCs, 1){
        res *= 2;
        res %= MOD;
    }

    cout<<res<<'\n';

    return 0;

}

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