oj.uz

답안 #993118

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
993118 2024-06-05T10:28:35 Z MarwenElarbi Event Hopping (BOI22_events) C++17
20 / 100
 289 ms 24512 KB 
#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;
vector<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 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]=max(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 {-1,-1};
    else if(l>=left&&r<=right) return segtree[pos];
    int mid=(r+l)/2;
    return max(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;
    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].se});
        sweep.pb({tab[i].se,1,i,tab[i].se});
    }
    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==1){
            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[s].fi==tab[e].fi&&tab[s].se==tab[e].se){
            cout <<1<<endl;
            continue;
        }else if(tab[e].se<=tab[s].fi&&tab[e].fi<tab[s].fi){
            cout <<"impossible"<<endl;
            continue;
        }else if(tab[e].fi<=tab[s].fi&&tab[s].fi<=tab[e].se&&tab[e].se<=tab[s].se){
            cout <<"impossible"<<endl;
            continue;
        }
        for (int i = 19; i >= 0; --i)
        {
            if(tab[dp[s][i]].se<tab[e].fi){
                ans+=(1<<i);
                s=dp[s][i];
            }
        }
        //cout <<s<<endl;
        if(tab[dp[s][0]].se<tab[e].fi) cout <<"impossible"<<endl;
        else if(tab[s].se<tab[e].fi) cout <<ans+2<<endl;
        else cout <<ans+1<<endl;
    }
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:48:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<query>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |     for (int i = 0; i < sweep.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~
events.cpp:58:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<query>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |     for (int i = 0; i < sweep.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 9816 KB Output is correct
2 Correct 244 ms 22872 KB Output is correct
3 Correct 244 ms 24000 KB Output is correct
4 Correct 272 ms 23596 KB Output is correct
5 Incorrect 255 ms 22972 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 9816 KB Output is correct
2 Correct 3 ms 9820 KB Output is correct
3 Correct 3 ms 9820 KB Output is correct
4 Correct 3 ms 9820 KB Output is correct
5 Incorrect 2 ms 9820 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 9816 KB Output is correct
2 Correct 3 ms 9820 KB Output is correct
3 Correct 3 ms 9820 KB Output is correct
4 Correct 3 ms 9820 KB Output is correct
5 Incorrect 2 ms 9820 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 9816 KB Output is correct
2 Correct 3 ms 9820 KB Output is correct
3 Correct 3 ms 9820 KB Output is correct
4 Correct 3 ms 9820 KB Output is correct
5 Incorrect 2 ms 9820 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 239 ms 23224 KB Output is correct
2 Correct 244 ms 23740 KB Output is correct
3 Correct 263 ms 22832 KB Output is correct
4 Correct 256 ms 24512 KB Output is correct
5 Correct 275 ms 23228 KB Output is correct
6 Correct 265 ms 23228 KB Output is correct
7 Correct 264 ms 23136 KB Output is correct
8 Correct 281 ms 23228 KB Output is correct
9 Correct 116 ms 22456 KB Output is correct
10 Correct 264 ms 22972 KB Output is correct
11 Correct 289 ms 22908 KB Output is correct
12 Correct 264 ms 22728 KB Output is correct

Subtask #6
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 9816 KB Output is correct
2 Correct 244 ms 22872 KB Output is correct
3 Correct 244 ms 24000 KB Output is correct
4 Correct 272 ms 23596 KB Output is correct
5 Incorrect 255 ms 22972 KB Output isn't correct
6 Halted 0 ms 0 KB -