Submission #532813

#	Time	Username	Problem	Language	Result	Execution time	Memory
532813		couplefire	Port Facility (JOI17_port_facility)	C++17	0 / 100	0 ms	204 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define f first
#define s second

const int N = 1<<20;
const int MOD = 1000000007;

int n; pii arr[N];
int id[N<<1];
int fa[N], siz[N];
pii seg[N<<2];

void init(int v = 1, int tl = 0, int tr = 2*N-1){
    if(tl==tr){
        seg[v] = {0, tl};
        return;
    }
    int tm = (tl+tr)>>1;
    init(v<<1, tl, tm);
    init(v<<1|1, tm+1, tr);
    seg[v] = max(seg[v<<1], seg[v<<1|1]);
}

void upd(int pos, int val, int v = 1, int tl = 0, int tr = 2*N-1){
    if(tr<pos || tl>pos) return;
    if(tl==tr){
        seg[v] = {val, pos};
        return;
    }
    int tm = (tl+tr)>>1;
    upd(pos, val, v<<1, tl, tm);
    upd(pos, val, v<<1|1, tm+1, tr);
    seg[v] = max(seg[v<<1], seg[v<<1|1]);
}

pii query(int l, int r, int v = 1, int tl = 0, int tr = 2*N-1){
    if(tr<l || tl>r) return pii{0, 0};
    if(l<=tl && tr<=r) return seg[v];
    int tm = (tl+tr)>>1;
    return max(query(l, r, v<<1, tl, tm), query(l, r, v<<1|1, tm+1, tr));
}

bool check(){
    vector<pii> l_st, r_st;
    for(int i = 1; i<=n; ++i){
        auto it = lower_bound(l_st.begin(), l_st.end(), pii{arr[i].f, 0});
        if(it==l_st.begin() || (*prev(it)).s<arr[i].f){
            while(!l_st.empty() && l_st.back().f>arr[i].f)
                l_st.pop_back();
            l_st.push_back(arr[i]);
        } else{
            it = lower_bound(r_st.begin(), r_st.end(), pii{arr[i].f, 0});
            if(it!=r_st.begin() && (*prev(it)).s>arr[i].f) 
                return 0;
            while(!r_st.empty() && r_st.back().f>arr[i].f)
                r_st.pop_back();
            r_st.push_back(arr[i]);
        }
    }
    return 1;
}

int find(int v){
    return v==fa[v]?v:fa[v]=find(fa[v]);
}

void unite(int u, int v){
    u = find(u), v = find(v);
    if(u==v) return;
    if(siz[u]>siz[v]) swap(u, v);
    fa[u] = v; siz[v] += siz[u];
}

int main(){
    // freopen("a.in", "r", stdin);
    cin.tie(0)->sync_with_stdio(0);
    cin >> n;
    for(int i = 1; i<=n; ++i)
        cin >> arr[i].f >> arr[i].s;
    sort(arr+1, arr+n+1, [&](const pii& a, const pii& b){return a.s<b.s;});
    for(int i = 1; i<=n; ++i)
        id[arr[i].f] = id[arr[i].s] = i;
    if(!check()){
        cout << 0 << '\n';
        exit(0);
    }
    init();
    for(int i = 1; i<=n; ++i)
        fa[i] = i, siz[i] = 1;
    for(int i = 1; i<=n; ++i){
        pii res = {0, 0};
        int mn = arr[i].f;
        while((res = query(1, arr[i].f-1)).f>arr[i].f){
            mn = min(mn, res.s);
            unite(i, id[res.s]);
            upd(res.s, 0);
        }
        upd(mn, arr[i].s);
    }
    int ans = 1;
    for(int i = 1; i<=n; ++i)
        if(fa[i]==i){
            ans = ans+ans;
            if(ans>=MOD) ans -= MOD;
        }
    cout << ans << '\n';
}

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