oj.uz

Submission #1081805

# Submission time Handle Problem Language Result Execution time Memory
1081805 2024-08-30T11:23:42 Z Tymond Event Hopping (BOI22_events) C++17
20 / 100
 105 ms 16096 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

const int MAXN = 1e5 + 7;
const int BASE = (1 << 17);
const int MAXK = 20;
int pos[MAXN];
pii tree[2 * BASE + 7];
int range[MAXK][MAXN];
vector<pair<pii, int>> vec;
int n, q;

pii smaller(pii x, pii y){
    if(x.fi != y.fi){
        return (x.fi < y.fi ? x : y);
    }
    return (x.se < y.se ? x : y);
}

void upd(int ind, pii val){
    ind += BASE;
    tree[ind] = val;
    ind /= 2;
    while(ind > 0){
        tree[ind] = smaller(tree[2 * ind], tree[2 * ind + 1]);
        ind /= 2;
    }
}

pii query(int v, int l, int p, int a, int b){
    if(p < a || b < l){
        return {1e9, 1e9};
    }

    if(a <= l && p <= b){
        return tree[v];
    }
    int mid = (l + p) / 2;
    return smaller(query(2 * v, l, mid, a, b), query(2 * v + 1, mid + 1, p, a, b));
}

void preprocessing(){
    for(int i = 0; i < 2 * BASE + 7; i++){
        tree[i] = {1e9, 1e9};
    }

    for(int i = 0; i < n; i++){
        upd(i, {vec[i].fi.fi , i});
    }
   // cout << "RANGES\n";
    for(int i = 0; i < n; i++){
        int l = 0;
        int p = i;
        int s;
        while(l < p){
            s = (l + p) / 2;
            if(vec[s].fi.se < vec[i].fi.fi){
                l = s + 1;
            }else{
                p = s;
            }
        }
      //  cout << i << ' ' << l << ' ';
        range[0][i] = query(1, 0, BASE - 1, l, i).se;
       // cout << range[0][i] << '\n';
    }

    for(int k = 1; k < MAXK; k++){
        for(int i = 0; i < n; i++){
            range[k][i] = range[k - 1][range[k - 1][i]];
        }
    }
}

int solve(int a, int b){
    //cout << a << ' ' << b << '\n';
    int res = 0;
    int akt = b;
    for(int i = MAXK - 1; i >= 0; i--){
        int nr = range[i][akt];
        if(vec[a].fi.se >= vec[nr].fi.se || nr == akt){
            continue;
        }
        res += (1 << i);
        akt = nr;
    }
    //cout << akt << '\n';
    if(vec[a].fi.se < vec[akt].fi.fi || vec[akt].fi.se < vec[a].fi.se){
       // cout << -1 << '\n';
        return -1;
    }
   // cout << res + 1 << '\n';
    return res + 1;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    cin >> n >> q;
    for(int i = 1; i <= n; i++){
        int s,e;
        cin >> s >> e;
        vec.pb({{e, s}, i});
    }

    sort(all(vec));
    for(int i = 0; i < n; i++){
        swap(vec[i].fi.fi, vec[i].fi.se);
        pos[vec[i].se] = i;
    }

    preprocessing();

    /*for(auto ele : vec){
        cout << ele.fi.fi << ' ' << ele.fi.se << '\n';
    }

    for(int i = 0; i < n; i++){
        for(int j = 0; j < MAXK / 2; j++){
            cout << range[j][i] << ' ';
        }
        cout << '\n';
    }*/

    while(q--){
        int s, e;
        cin >> s >> e;
        s = pos[s];
        e = pos[e];
       // cout << "PYTANIE: " << s << ' ' << e << '\n';
        if(s == e){
            cout << 0 << '\n';
            continue;
        }

        int ans = solve(s, e);
        if(ans == -1){
            cout << "impossible\n";
        }else{
            cout << ans << '\n';
        }
    }

    return 0;
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 76 ms 15556 KB Output is correct
3 Correct 77 ms 15556 KB Output is correct
4 Correct 81 ms 15560 KB Output is correct
5 Correct 78 ms 15564 KB Output is correct
6 Correct 79 ms 15716 KB Output is correct
7 Correct 78 ms 15808 KB Output is correct
8 Incorrect 73 ms 16068 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 1 ms 2392 KB Output is correct
3 Correct 2 ms 2652 KB Output is correct
4 Correct 2 ms 2648 KB Output is correct
5 Correct 2 ms 2652 KB Output is correct
6 Incorrect 2 ms 2532 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 1 ms 2392 KB Output is correct
3 Correct 2 ms 2652 KB Output is correct
4 Correct 2 ms 2648 KB Output is correct
5 Correct 2 ms 2652 KB Output is correct
6 Incorrect 2 ms 2532 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 1 ms 2392 KB Output is correct
3 Correct 2 ms 2652 KB Output is correct
4 Correct 2 ms 2648 KB Output is correct
5 Correct 2 ms 2652 KB Output is correct
6 Incorrect 2 ms 2532 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 77 ms 15672 KB Output is correct
2 Correct 77 ms 15484 KB Output is correct
3 Correct 82 ms 15552 KB Output is correct
4 Correct 75 ms 16068 KB Output is correct
5 Correct 105 ms 16096 KB Output is correct
6 Correct 99 ms 15664 KB Output is correct
7 Correct 104 ms 15648 KB Output is correct
8 Correct 99 ms 15816 KB Output is correct
9 Correct 56 ms 13760 KB Output is correct
10 Correct 81 ms 15300 KB Output is correct
11 Correct 86 ms 15300 KB Output is correct
12 Correct 80 ms 15456 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 76 ms 15556 KB Output is correct
3 Correct 77 ms 15556 KB Output is correct
4 Correct 81 ms 15560 KB Output is correct
5 Correct 78 ms 15564 KB Output is correct
6 Correct 79 ms 15716 KB Output is correct
7 Correct 78 ms 15808 KB Output is correct
8 Incorrect 73 ms 16068 KB Output isn't correct
9 Halted 0 ms 0 KB -