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Submission #599445

# Submission time Handle Problem Language Result Execution time Memory
599445 2022-07-19T14:11:48 Z alexander707070 Event Hopping (BOI22_events) C++17
30 / 100
 347 ms 137004 KB 
#include<bits/stdc++.h>
#define MAXN 400007
using namespace std;

struct event{
    long long s;
    long long e;
    int id;

    inline friend bool operator < (event fr,event sc){
        if(fr.e!=sc.e)return fr.e<sc.e;
        return fr.s<=sc.s;
    }
};

int n,cnt,q,S,E,ans;
int st[MAXN],et[MAXN];
int pos[MAXN],parent[MAXN];
event e[MAXN];
vector<int> w;
map<int,int> mp;

pair<int,int> mins[8*MAXN];

pair<int,int> best(pair<int,int> fr,pair<int,int> sc){
    if(fr.second<=sc.second)return fr;
    return sc;
}

void update(int v,int l,int r,int pos,int val,int id){
    if(l==r){
        if(val<mins[v].second or val==10000000){
            mins[v]={id,val};
        }
    }else{
        int tt=(l+r)/2;
        if(pos<=tt)update(2*v,l,tt,pos,val,id);
        else update(2*v+1,tt+1,r,pos,val,id);
        mins[v]=best(mins[2*v],mins[2*v+1]);
    }
}

pair<int,int> getmin(int v,int l,int r,int ll,int rr){
    if(ll>rr)return {0,100000000};
    if(l==ll and r==rr){
        return mins[v];
    }else{
        int tt=(l+r)/2;
        return best( getmin(2*v,l,tt,ll,min(tt,rr)) , getmin(2*v+1,tt+1,r,max(tt+1,ll),rr) );
    }
}

int dp[MAXN][20];

void calc(){
    for(int f=0;f<20;f++){
        for(int i=1;i<=n;i++){
            if(f==0)dp[i][f]=parent[i];
            else dp[i][f]=dp[dp[i][f-1]][f-1];
        }
    }
}

int bin(int id,int id2){

    if(id==id2)return 0;
    if(et[id]<st[id2])return -1;
    if(et[id2]>et[id])return -1;
    if(et[id2]>=st[id])return 1;

    int res=0;
    for(int i=19;i>=0;i--){
        if(dp[id][i]!=0 and st[dp[id][i]]>et[id2]){
            id=dp[id][i];
            res+=(1<<i);
        }
    }

    if(parent[id]==0)return -1;
    if(parent[id]==id2)return res+1;
    return res+2;
}

int main(){

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin>>n>>q;
    for(int i=1;i<=n;i++){
        cin>>st[i]>>et[i];
        e[i]={st[i],et[i],i};
        w.push_back(e[i].s);
        w.push_back(e[i].e);
    }

    sort(w.begin(),w.end());
    for(int i=0;i<w.size();i++){
        if(i>0 and w[i]!=w[i-1])cnt++;
        mp[w[i]]=cnt;
    }

    for(int i=1;i<=n;i++){
        e[i].s=mp[e[i].s];
        e[i].e=mp[e[i].e];
        pos[e[i].id]=i;
    }

    for(int i=0;i<=cnt;i++){
        update(1,0,cnt,i,10000000,0);
    }

    sort(e+1,e+n+1);
    for(int i=1;i<=n;i++){
        parent[e[i].id]=getmin(1,0,cnt,e[i].s,e[i].e).first;
        update(1,0,cnt,e[i].e,e[i].s,e[i].id);
    }
    calc();

    for(int i=1;i<=q;i++){
        cin>>S>>E;
        ans=bin(E,S);
        if(ans==-1)cout<<"impossible\n";
        else cout<<ans<<"\n";
    }


    return 0;
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:99:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   99 |     for(int i=0;i<w.size();i++){
      |                 ~^~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 178 ms 20276 KB Output is correct
3 Correct 219 ms 20120 KB Output is correct
4 Correct 210 ms 20172 KB Output is correct
5 Correct 196 ms 20788 KB Output is correct
6 Correct 220 ms 21120 KB Output is correct
7 Correct 195 ms 21300 KB Output is correct
8 Correct 219 ms 27384 KB Output is correct
9 Correct 207 ms 27408 KB Output is correct
10 Correct 206 ms 20508 KB Output is correct
11 Correct 239 ms 24456 KB Output is correct
12 Correct 131 ms 20632 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 2 ms 596 KB Output is correct
8 Correct 2 ms 596 KB Output is correct
9 Runtime error 189 ms 137004 KB Execution killed with signal 11
10 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 2 ms 596 KB Output is correct
8 Correct 2 ms 596 KB Output is correct
9 Runtime error 189 ms 137004 KB Execution killed with signal 11
10 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 2 ms 596 KB Output is correct
8 Correct 2 ms 596 KB Output is correct
9 Runtime error 189 ms 137004 KB Execution killed with signal 11
10 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 226 ms 20136 KB Output is correct
2 Correct 219 ms 20152 KB Output is correct
3 Correct 246 ms 20112 KB Output is correct
4 Correct 231 ms 27496 KB Output is correct
5 Correct 206 ms 20592 KB Output is correct
6 Correct 267 ms 27092 KB Output is correct
7 Correct 276 ms 27032 KB Output is correct
8 Correct 279 ms 27264 KB Output is correct
9 Correct 275 ms 26360 KB Output is correct
10 Correct 323 ms 26744 KB Output is correct
11 Correct 288 ms 26584 KB Output is correct
12 Correct 347 ms 26772 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 178 ms 20276 KB Output is correct
3 Correct 219 ms 20120 KB Output is correct
4 Correct 210 ms 20172 KB Output is correct
5 Correct 196 ms 20788 KB Output is correct
6 Correct 220 ms 21120 KB Output is correct
7 Correct 195 ms 21300 KB Output is correct
8 Correct 219 ms 27384 KB Output is correct
9 Correct 207 ms 27408 KB Output is correct
10 Correct 206 ms 20508 KB Output is correct
11 Correct 239 ms 24456 KB Output is correct
12 Correct 131 ms 20632 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 0 ms 340 KB Output is correct
15 Correct 2 ms 468 KB Output is correct
16 Correct 1 ms 468 KB Output is correct
17 Correct 1 ms 468 KB Output is correct
18 Correct 1 ms 468 KB Output is correct
19 Correct 2 ms 596 KB Output is correct
20 Correct 2 ms 596 KB Output is correct
21 Runtime error 189 ms 137004 KB Execution killed with signal 11
22 Halted 0 ms 0 KB -