oj.uz

답안 #599440

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
599440 2022-07-19T14:10:50 Z alexander707070 Event Hopping (BOI22_events) C++17
0 / 100
 195 ms 19780 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 i=1;i<=n;i++){
        for(int f=0;f<20;f++){
            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
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Incorrect 194 ms 19744 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Incorrect 2 ms 468 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Incorrect 2 ms 468 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Incorrect 2 ms 468 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 195 ms 19780 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Incorrect 194 ms 19744 KB Output isn't correct
3 Halted 0 ms 0 KB -