Submission #1271242

#	Time	Username	Problem	Language	Result	Execution time	Memory
1271242		trandangquang	Port Facility (JOI17_port_facility)	C++20	0 / 100	0 ms	320 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;

#define foru(i,a,b) for(int i=(a); i<=(b); ++i)
#define ford(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i,a) for(int i=0; i<(a); ++i)
#define bit(s,i) (((s)>>(i))&1)
#define all(a) (a).begin(),(a).end()
#define sz(a) (int)(a).size()
#define ii pair<int,int>
#define fi first
#define se second
#define eb emplace_back
#define pb push_back
#define ll long long
#define __builtin_popcount(a) __builtin_popcountll(a)

template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;}
template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;}

const int N=2e6+5;
const int mod=1e9+7;

int n; ii cont[N];
ii st[N<<2];

void upd(int x, ii val){
    int id=1, l=1, r=2*n;
    while(l<r){
        int mid=(l+r)>>1;
        if(x<=mid){
            r=mid;
            id=id<<1;
        } else{
            l=mid+1;
            id=id<<1|1;
        }
    }
    st[id]=val;
    while(id>1){
        id/=2;
        st[id]=max(st[id<<1], st[id<<1|1]);
    }
}

ii get(int u, int v, int id=1, int l=1, int r=2*n){
    if(u>r||v<l) return {0,0};
    if(u<=l&&r<=v) return st[id];
    int mid=(l+r)>>1;
    return max(get(u,v,id<<1,l,mid), get(u,v,id<<1|1,mid+1,r));
}


int stk[N],top;
int num[N],ncc;
bool vis[N];
vector<int> hihi[2];

void dfs(int u){
    vis[u]=true;
    hihi[num[u]].eb(u);
    upd(cont[u].fi,{0,0});

    while(true){
        ii tmp=get(cont[u].fi+1,cont[u].se-1);
        if(tmp.fi<cont[u].se) break;
        num[tmp.se]=num[u]^1;
        dfs(tmp.se);
    }
}

void solve(){
    cin>>n;
    foru(i,1,n) cin>>cont[i].fi>>cont[i].se;

    sort(cont+1, cont+1+n);
    foru(i,1,n){
        upd(cont[i].fi, {cont[i].se, i});
    }

    int res=1;
    foru(i,1,n) if(!vis[i]){
        ++ncc;
        dfs(i);
        foru(j,0,1){
            sort(all(hihi[j]));

            top=0;
            for(int k:hihi[j]){
                while(top && cont[stk[top]].se<cont[k].fi) --top;
                if(top && cont[k].se>cont[stk[top]].se){
                    cout<<"0\n";
                    return;
                }
                stk[++top]=k;
            }

            hihi[j].clear();
        }
        res=res+res;
        if(res>=mod) res-=mod;
    }

    cout<<res<<'\n';
}

int32_t main(){
    #define task "test"
    if(fopen(task".inp","r")){
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    cin.tie(0)->sync_with_stdio(0);

    solve();
}

Compilation message (stderr)

port_facility.cpp: In function 'int32_t main()':
port_facility.cpp:110:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  110 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
port_facility.cpp:111:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  111 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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