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Submission #599504

# Submission time Handle Problem Language Result Execution time Memory
599504 2022-07-19T14:44:00 Z alexander707070 Event Hopping (BOI22_events) C++14
35 / 100
 1500 ms 23344 KB 
#include<bits/stdc++.h>
#define MAXN 400007
using namespace std;

struct event{
    int s;
    int 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 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];
    }

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

    sort(e+1,e+n+1);

    for(int i=1;i<=n;i++){
        pair<int,int> sol={0,100000000};
        for(int f=e[i].s;f<=e[i].e;f++){
            sol=best(sol,mins[f]);
        }
        //parent[e[i].id]=getmin(1,0,cnt,e[i].s,e[i].e).first;
        parent[e[i].id]=sol.first;
        //update(1,0,cnt,e[i].e,e[i].s,e[i].id);
        mins[e[i].e]=best(mins[e[i].e],{e[i].id,e[i].s});
    }
    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 1 ms 340 KB Output is correct
2 Correct 150 ms 17436 KB Output is correct
3 Correct 162 ms 17312 KB Output is correct
4 Correct 182 ms 17300 KB Output is correct
5 Correct 172 ms 17936 KB Output is correct
6 Correct 162 ms 18508 KB Output is correct
7 Correct 160 ms 18704 KB Output is correct
8 Correct 157 ms 23256 KB Output is correct
9 Correct 160 ms 23276 KB Output is correct
10 Correct 164 ms 17736 KB Output is correct
11 Correct 165 ms 19880 KB Output is correct
12 Correct 93 ms 17860 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 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 468 KB Output is correct
8 Correct 2 ms 468 KB Output is correct
9 Correct 1 ms 468 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 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 468 KB Output is correct
8 Correct 2 ms 468 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 468 KB Output is correct
15 Correct 1 ms 468 KB Output is correct
16 Correct 2 ms 596 KB Output is correct
17 Correct 2 ms 596 KB Output is correct
18 Correct 1 ms 468 KB Output is correct
19 Correct 36 ms 2676 KB Output is correct
20 Correct 29 ms 2640 KB Output is correct
21 Correct 31 ms 2892 KB Output is correct
22 Correct 34 ms 2900 KB Output is correct
23 Correct 39 ms 3056 KB Output is correct
24 Correct 44 ms 3100 KB Output is correct
25 Correct 28 ms 2680 KB Output is correct

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 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 468 KB Output is correct
8 Correct 2 ms 468 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 468 KB Output is correct
15 Correct 1 ms 468 KB Output is correct
16 Correct 2 ms 596 KB Output is correct
17 Correct 2 ms 596 KB Output is correct
18 Correct 1 ms 468 KB Output is correct
19 Correct 124 ms 18720 KB Output is correct
20 Correct 116 ms 17820 KB Output is correct
21 Correct 1119 ms 18476 KB Output is correct
22 Correct 128 ms 20468 KB Output is correct
23 Execution timed out 1578 ms 16252 KB Time limit exceeded
24 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 140 ms 17352 KB Output is correct
2 Correct 157 ms 17380 KB Output is correct
3 Correct 199 ms 17312 KB Output is correct
4 Correct 178 ms 23344 KB Output is correct
5 Correct 166 ms 17632 KB Output is correct
6 Correct 234 ms 23080 KB Output is correct
7 Correct 209 ms 22924 KB Output is correct
8 Correct 205 ms 23100 KB Output is correct
9 Execution timed out 1570 ms 14424 KB Time limit exceeded
10 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 150 ms 17436 KB Output is correct
3 Correct 162 ms 17312 KB Output is correct
4 Correct 182 ms 17300 KB Output is correct
5 Correct 172 ms 17936 KB Output is correct
6 Correct 162 ms 18508 KB Output is correct
7 Correct 160 ms 18704 KB Output is correct
8 Correct 157 ms 23256 KB Output is correct
9 Correct 160 ms 23276 KB Output is correct
10 Correct 164 ms 17736 KB Output is correct
11 Correct 165 ms 19880 KB Output is correct
12 Correct 93 ms 17860 KB Output is correct
13 Correct 0 ms 340 KB Output is correct
14 Correct 0 ms 340 KB Output is correct
15 Correct 1 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 468 KB Output is correct
20 Correct 2 ms 468 KB Output is correct
21 Correct 1 ms 468 KB Output is correct
22 Correct 1 ms 340 KB Output is correct
23 Correct 0 ms 340 KB Output is correct
24 Correct 1 ms 468 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 468 KB Output is correct
27 Correct 1 ms 468 KB Output is correct
28 Correct 2 ms 596 KB Output is correct
29 Correct 2 ms 596 KB Output is correct
30 Correct 1 ms 468 KB Output is correct
31 Correct 36 ms 2676 KB Output is correct
32 Correct 29 ms 2640 KB Output is correct
33 Correct 31 ms 2892 KB Output is correct
34 Correct 34 ms 2900 KB Output is correct
35 Correct 39 ms 3056 KB Output is correct
36 Correct 44 ms 3100 KB Output is correct
37 Correct 28 ms 2680 KB Output is correct
38 Correct 1 ms 340 KB Output is correct
39 Correct 0 ms 340 KB Output is correct
40 Correct 1 ms 468 KB Output is correct
41 Correct 1 ms 468 KB Output is correct
42 Correct 1 ms 468 KB Output is correct
43 Correct 1 ms 468 KB Output is correct
44 Correct 2 ms 596 KB Output is correct
45 Correct 2 ms 596 KB Output is correct
46 Correct 1 ms 468 KB Output is correct
47 Correct 124 ms 18720 KB Output is correct
48 Correct 116 ms 17820 KB Output is correct
49 Correct 1119 ms 18476 KB Output is correct
50 Correct 128 ms 20468 KB Output is correct
51 Execution timed out 1578 ms 16252 KB Time limit exceeded
52 Halted 0 ms 0 KB -