oj.uz

Submission #595630

# Submission time Handle Problem Language Result Execution time Memory
595630 2022-07-13T22:20:54 Z definitelynotmee Event Hopping (BOI22_events) C++
30 / 100
 121 ms 13448 KB 
#include<bits/stdc++.h>
#define ff first
#define ss second
#define all(x) x.begin(), x.end()
using namespace std;
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
template<typename T>
using matrix = vector<vector<T>>;
const int INF = 1<<30;

int main() {
    cin.tie(0)->sync_with_stdio(0);

    int n, q;
    cin >> n >> q;
    vector<pii> v(n);
    for(pii& i : v){
        cin >> i.ff >> i.ss;
        i.ff = INF-i.ff;
        i.ss = INF-i.ss;
        swap(i.ff,i.ss);
    }
    // cout << "----------\n";
    // for(pii i : v)
    //     cout << i.ff << ' ' << i.ss << '\n';
    // cout << "----------\n";
    vector<int>o(n);
    iota(all(o),0);
    sort(all(o),[&](int a, int b){
        return v[a] > v[b];
    });

    vector<int> jmp(n);
    vector<int> st;

    for(int i : o){
        int ini = 0, fim = st.size();
        while(ini!=fim){
            int m = (ini+fim)>>1;
            if(v[st[m]].ff <= v[i].ss)
                fim = m;
            else ini = m+1;
        }
        if(ini == st.size()){
            jmp[i] = i;
        } else jmp[i] = st[ini];
        
        while(!st.empty() && v[st.back()].ss <= v[i].ss)
            st.pop_back();
        if(st.empty() || v[st.back()].ff > v[i].ff)
            st.push_back(i);
        // cout << i << ":\n";
        // for(int i : st)
        //     cout << i << ' ';
        // cout << '\n';
    }

    matrix<int> lift(20,vector<int>(n));
    for(int i = 0; i < n; i++){
        lift[0][i] = jmp[i]; 
        // cout << jmp[i] << ' ';
    }
    // cout << '\n';
    for(int i = 1; i < 20; i++){
        for(int j = 0; j < n; j++){
            lift[i][j] = lift[i-1][lift[i-1][j]];
        }
    }
    
    while(q--){
        int a, b;
        cin >> a >> b;
        a--, b--;
        swap(a,b);
        if(v[a].ff > v[b].ff){
            cout << "impossible\n";
            continue;
        }
        if(v[a] == v[b]){
            cout << 0 << '\n';
            continue;
        }
        if(v[a].ss >= v[b].ff){
            cout << 1 << '\n';
            continue;
        }
        int ct = 2;
        for(int i = 19; i >= 0; i--){
            if(v[lift[i][a]].ss < v[b].ff)
                ct+=1<<i, a = lift[i][a];
        }
        a = lift[0][a];
        if(v[a].ss >= v[b].ff){
            cout << ct << '\n';
        } else {
            cout << "impossible\n";
        }
    }

}

Compilation message

events.cpp: In function 'int main()':
events.cpp:46:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |         if(ini == st.size()){
      |            ~~~~^~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 65 ms 10856 KB Output is correct
3 Correct 77 ms 10816 KB Output is correct
4 Correct 103 ms 10764 KB Output is correct
5 Correct 116 ms 10828 KB Output is correct
6 Correct 101 ms 10932 KB Output is correct
7 Correct 87 ms 10836 KB Output is correct
8 Correct 93 ms 11296 KB Output is correct
9 Correct 98 ms 11336 KB Output is correct
10 Correct 105 ms 11212 KB Output is correct
11 Correct 83 ms 11100 KB Output is correct
12 Correct 53 ms 13448 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Incorrect 1 ms 340 KB Output isn't correct
10 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Incorrect 1 ms 340 KB Output isn't correct
10 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Incorrect 1 ms 340 KB Output isn't correct
10 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 65 ms 10840 KB Output is correct
2 Correct 80 ms 10812 KB Output is correct
3 Correct 121 ms 10820 KB Output is correct
4 Correct 94 ms 11320 KB Output is correct
5 Correct 88 ms 11204 KB Output is correct
6 Correct 108 ms 10952 KB Output is correct
7 Correct 79 ms 10964 KB Output is correct
8 Correct 75 ms 11220 KB Output is correct
9 Correct 36 ms 10568 KB Output is correct
10 Correct 98 ms 10572 KB Output is correct
11 Correct 79 ms 10580 KB Output is correct
12 Correct 78 ms 10576 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 65 ms 10856 KB Output is correct
3 Correct 77 ms 10816 KB Output is correct
4 Correct 103 ms 10764 KB Output is correct
5 Correct 116 ms 10828 KB Output is correct
6 Correct 101 ms 10932 KB Output is correct
7 Correct 87 ms 10836 KB Output is correct
8 Correct 93 ms 11296 KB Output is correct
9 Correct 98 ms 11336 KB Output is correct
10 Correct 105 ms 11212 KB Output is correct
11 Correct 83 ms 11100 KB Output is correct
12 Correct 53 ms 13448 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 340 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 1 ms 340 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 1 ms 340 KB Output is correct
21 Incorrect 1 ms 340 KB Output isn't correct
22 Halted 0 ms 0 KB -