oj.uz

Submission #993465

# Submission time Handle Problem Language Result Execution time Memory
993465 2024-06-05T17:35:11 Z MarwenElarbi Event Hopping (BOI22_events) C++17
30 / 100
 315 ms 24252 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;
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;
    }
}

Compilation message

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
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 247 ms 20444 KB Output is correct
3 Correct 240 ms 20668 KB Output is correct
4 Correct 286 ms 20668 KB Output is correct
5 Correct 307 ms 20028 KB Output is correct
6 Correct 247 ms 20348 KB Output is correct
7 Correct 247 ms 20044 KB Output is correct
8 Correct 236 ms 24252 KB Output is correct
9 Correct 238 ms 23484 KB Output is correct
10 Correct 249 ms 23412 KB Output is correct
11 Correct 269 ms 23412 KB Output is correct
12 Correct 215 ms 22788 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 2 ms 600 KB Output is correct
5 Correct 2 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Incorrect 2 ms 592 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 2 ms 600 KB Output is correct
5 Correct 2 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Incorrect 2 ms 592 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 2 ms 600 KB Output is correct
5 Correct 2 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Incorrect 2 ms 592 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 239 ms 20168 KB Output is correct
2 Correct 260 ms 19840 KB Output is correct
3 Correct 253 ms 20328 KB Output is correct
4 Correct 252 ms 20400 KB Output is correct
5 Correct 252 ms 20276 KB Output is correct
6 Correct 315 ms 20120 KB Output is correct
7 Correct 249 ms 20060 KB Output is correct
8 Correct 254 ms 20152 KB Output is correct
9 Correct 99 ms 19640 KB Output is correct
10 Correct 250 ms 20076 KB Output is correct
11 Correct 248 ms 19952 KB Output is correct
12 Correct 261 ms 19720 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 247 ms 20444 KB Output is correct
3 Correct 240 ms 20668 KB Output is correct
4 Correct 286 ms 20668 KB Output is correct
5 Correct 307 ms 20028 KB Output is correct
6 Correct 247 ms 20348 KB Output is correct
7 Correct 247 ms 20044 KB Output is correct
8 Correct 236 ms 24252 KB Output is correct
9 Correct 238 ms 23484 KB Output is correct
10 Correct 249 ms 23412 KB Output is correct
11 Correct 269 ms 23412 KB Output is correct
12 Correct 215 ms 22788 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 2 ms 600 KB Output is correct
17 Correct 2 ms 604 KB Output is correct
18 Correct 1 ms 604 KB Output is correct
19 Incorrect 2 ms 592 KB Output isn't correct
20 Halted 0 ms 0 KB -