Submission #447696

#	Time	Username	Problem	Language	Result	Execution time	Memory
447696		Haruto810198	Port Facility (JOI17_port_facility)	C++17	22 / 100	5145 ms	1048580 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];

list<int> qu;

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

int CCs;
set<int> CC[MAX];

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

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(u, v);
            swap(pu, pv);
        }

        if(dep[pu] == dep[pv]){
            dep[pu]++;
        }

        pa[pv] = pu;
        for(int i : CC[pv]){
            CC[pu].insert(i);
        }

        if(tag[u] == -1 and tag[v] == -1){
            tag[u] = 0;
            tag[v] = 1;
        }
        else if(tag[u] != -1 and tag[v] == -1){
            tag[v] = 1 - tag[u];
        }
        else if(tag[u] == tag[v]){
            for(int i : CC[pv]){
                tag[i] = 1 - tag[i];
            }
        }
        else if(tag[u] != tag[v]){
            /// do nothing
        }

    }
    else if(pu == pv){
        if(tag[u] + tag[v] != 1){
            res = 0;
        }
    }

}

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[i] + tag[v] != 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, 1, n, 1){
        pa[i] = i;
        dep[i] = 0;
        tag[i] = -1;
        vis[i] = 0;
        CC[i].insert(i);
    }
    CCs = n;

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

        if(op[i] > 0){
            qu.pb(op[i]);
        }
        else if(op[i] < 0){

            popped[-op[i]] = 1;

            auto it = prev(qu.end());

            for( ; *it!= -op[i]; it = prev(it)){
                if(popped[*it] == 1){
                    qu.erase(it);
                }
                else{
                    edge[-op[i]].pb(*it);
                    edge[*it].pb(-op[i]);
                    uni(-op[i], *it);
                }
            }

            qu.erase(it);

        }

        if(res == 0){
            break;
        }

    }

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

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

    cout<<res<<'\n';

    return 0;

}

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