제출 #993465

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
993465		MarwenElarbi	Event Hopping (BOI22_events)	C++17	30 / 100	315 ms	24252 KiB

events

#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define pb push_back
const int nax=3e5+5;
pair<int,int> segtree[4*nax];
struct query{
    int x,type,idx,value;
};
bool compare(query a,query b){
    if(a.x!=b.x) return a.x<b.x;
    else if(a.type!=b.type) return a.type<b.type;
    else if(a.value!=b.value) return a.value<b.value;
    else return a.idx<b.idx;
}
vector<query> sweep;
void build(int pos,int l,int r){
    if(l==r){
        segtree[pos]={sweep[l].value,sweep[l].idx};
        return;
    }
    int mid=(r+l)/2;
    build(pos*2+1,l,mid);
    build(pos*2+2,mid+1,r);
    segtree[pos]=min(segtree[pos*2+1],segtree[pos*2+2]);
    return;
}
pair<int,int> query(int pos,int l,int r,int left,int right){
    if(l>r||l>right||r<left) return {1e9,1e9};
    else if(l>=left&&r<=right) {
        return segtree[pos];
    }
    int mid=(r+l)/2;
    return min(query(pos*2+1,l,mid,left,right),query(pos*2+2,mid+1,r,left,right));
}
int main(){
    int n,q;
    cin>>n>>q;
    for (int i = 0; i < n*2*4; ++i)
    {
        segtree[i]={1e9,1e9};
    }
    vector<pair<int,int>> tab(n);
    for (int i = 0; i < n; ++i)
    {
        cin>>tab[i].fi>>tab[i].se;
        sweep.pb({tab[i].fi,0,i,tab[i].fi});
        sweep.pb({tab[i].se,1,i,tab[i].fi});
    }
    sort(sweep.begin(),sweep.end(),compare);
    pair<int,int> pos[n];
    for (int i = 0; i < sweep.size(); ++i)
    {
        if(sweep[i].type==0){
            pos[sweep[i].idx].fi=i;
        }else{
            pos[sweep[i].idx].se=i;
        }
    }
    build(0,0,sweep.size()-1);
    int dp[n][20];
    for (int i = 0; i < sweep.size(); ++i)
    {
        if(sweep[i].type==0){
            dp[sweep[i].idx][0]=query(0,0,sweep.size()-1,pos[sweep[i].idx].fi,pos[sweep[i].idx].se).se;
        }
    }
    for (int j = 1; j < 20; ++j)
    {
        for (int i = 0; i < n; ++i)
        {
            dp[i][j]=dp[dp[i][j-1]][j-1];
        }
    }
    while(q--){
        int s,e;
        cin>>s>>e;
        s--;e--;
        int ans=0;
        if(s==e){
            cout <<0<<endl;
            continue;
        }else if(tab[e].se<tab[s].se){
            cout <<"impossible"<<endl;
            continue;
        }else if(tab[e].fi<=tab[s].se&&tab[s].se<=tab[e].se){
            cout <<1<<endl;
            continue;
        }
        for (int i = 19; i >= 0 ; i--)
        {
            if(tab[dp[e][i]].fi>tab[s].fi){
                ans+=(1<<i);
                e=dp[e][i];
            }
        }
        //cout <<e<<endl;
        if(tab[dp[e][0]].fi > tab[s].se){
            cout <<"impossible"<<endl;
            continue;
        }else if(tab[dp[e][0]].se>tab[s].se) cout <<ans+2<<endl;
        else cout <<ans+1<<endl;
    }
}

컴파일 시 표준 에러 (stderr) 메시지

events.cpp: In function 'int main()':
events.cpp:54:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<query>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |     for (int i = 0; i < sweep.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~
events.cpp:64:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<query>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |     for (int i = 0; i < sweep.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 20 / 20
• Subtask 6: 0 / 30