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Submission #993149

# Submission time Handle Problem Language Result Execution time Memory
993149 2024-06-05T11:02:55 Z MarwenElarbi Event Hopping (BOI22_events) C++17
20 / 100
 365 ms 31936 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];
    int dp1[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()-1,0,pos[sweep[i].idx].se).se;
            dp1[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];
            dp1[i][j]=dp1[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 <<"nab "<<s<<" "<<ans<<endl;
        for (int i = 19; i >= 0; --i)
        {
            if(tab[dp1[s][i]].se<tab[e].fi){
                ans+=(1<<i);
                s=dp[s][i];
            }
        }
        if(tab[dp1[s][0]].se<tab[e].fi) cout <<"impossible"<<endl;
        else if(tab[s].se>=tab[e].fi) cout <<ans+1<<endl;
        else if(tab[dp1[s][0]].se>tab[e].se) 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:47:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<query>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |     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

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9816 KB Output is correct
2 Correct 291 ms 31684 KB Output is correct
3 Correct 296 ms 30820 KB Output is correct
4 Correct 314 ms 31492 KB Output is correct
5 Correct 325 ms 30908 KB Output is correct
6 Correct 324 ms 30820 KB Output is correct
7 Correct 304 ms 30904 KB Output is correct
8 Incorrect 261 ms 31076 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9820 KB Output is correct
2 Correct 2 ms 9600 KB Output is correct
3 Correct 3 ms 10072 KB Output is correct
4 Correct 6 ms 9820 KB Output is correct
5 Incorrect 4 ms 9848 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9820 KB Output is correct
2 Correct 2 ms 9600 KB Output is correct
3 Correct 3 ms 10072 KB Output is correct
4 Correct 6 ms 9820 KB Output is correct
5 Incorrect 4 ms 9848 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9820 KB Output is correct
2 Correct 2 ms 9600 KB Output is correct
3 Correct 3 ms 10072 KB Output is correct
4 Correct 6 ms 9820 KB Output is correct
5 Incorrect 4 ms 9848 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 277 ms 30820 KB Output is correct
2 Correct 309 ms 30840 KB Output is correct
3 Correct 301 ms 30652 KB Output is correct
4 Correct 265 ms 31164 KB Output is correct
5 Correct 322 ms 31164 KB Output is correct
6 Correct 365 ms 31676 KB Output is correct
7 Correct 330 ms 31936 KB Output is correct
8 Correct 284 ms 31312 KB Output is correct
9 Correct 130 ms 30652 KB Output is correct
10 Correct 294 ms 30548 KB Output is correct
11 Correct 273 ms 30396 KB Output is correct
12 Correct 288 ms 30652 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9816 KB Output is correct
2 Correct 291 ms 31684 KB Output is correct
3 Correct 296 ms 30820 KB Output is correct
4 Correct 314 ms 31492 KB Output is correct
5 Correct 325 ms 30908 KB Output is correct
6 Correct 324 ms 30820 KB Output is correct
7 Correct 304 ms 30904 KB Output is correct
8 Incorrect 261 ms 31076 KB Output isn't correct
9 Halted 0 ms 0 KB -