oj.uz

답안 #993085

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
993085 2024-06-05T10:00:21 Z MarwenElarbi Event Hopping (BOI22_events) C++17
0 / 100
 8 ms 13244 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=2e5+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 {0,-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(){
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
    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];
    for (int i = 0; i < sweep.size(); ++i)
    {
        if(sweep[i].type==1){
            dp[sweep[i].idx][0]=query(0,0,sweep.size()-1,pos[sweep[i].idx].fi,pos[sweep[i].idx].se).se;
        }
    }
    /*for (int i = 0; i < n; ++i)
    {
        cout <<dp[i][0]<<" ";
    }cout <<endl;*/
    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=1;
        if(s==e){
            cout <<0<<endl;
            continue;
        }else if(tab[e].se<=tab[s].fi){
            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];
            } 
        }
        if(tab[dp[s][0]].se<tab[e].fi) cout <<"impossible"<<endl;
        else cout <<ans+1<<endl;
    }
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:51:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<query>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |     for (int i = 0; i < sweep.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~
events.cpp:61:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<query>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for (int i = 0; i < sweep.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~
events.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
events.cpp:38:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 7 ms 13148 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 8 ms 13148 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 8 ms 13148 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 8 ms 13148 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 6 ms 13244 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 7 ms 13148 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -