Submission #799679

#	Time	Username	Problem	Language	Result	Execution time	Memory
799679		TB_	Event Hopping (BOI22_events)	C++17	100 / 100	615 ms	327564 KiB

events

#include <bits/stdc++.h>
using namespace std;

// #undef _GLIBCXX_DEBUG                // disable run-time bound checking, etc
// #pragma GCC optimize("Ofast,inline") // Ofast = O3,fast-math,allow-store-data-races,no-protect-parens
// #pragma GCC optimize ("unroll-loops")

// #pragma GCC target("bmi,bmi2,lzcnt,popcnt")                      // bit manipulation
// #pragma GCC target("movbe")                                      // byte swap
// #pragma GCC target("aes,pclmul,rdrnd")                           // encryption
// #pragma GCC target("avx,avx2,f16c,fma,sse3,ssse3,sse4.1,sse4.2") // SIMD

// #include <bits/extc++.h>
// using namespace __gnu_pbds;
// template<class T>using ordered_set = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
// template<class T>using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define ll long long
#define INF (ll)1e9+7
#define fo(i, n) for(int i=0;i<((ll)n);i++)
#define deb(x) cout << #x << " = " << x << endl;
#define deb2(x, y) cout << #x << " = " << x << ", " << #y << " = " << y << endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define LSOne(S) ((S) & (-S))
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
inline int readint(){ int v = 0; char c; while((c = getchar()) != EOF && c != ' ' && c != '\n'){ v *= 10; v += c - '0'; } return v; }
inline int readintsigned() { int v = 0; int sign = 1; char c = getchar(); if (c == '-') { sign = -1; } else { v += c - '0'; } while ((c = getchar()) != EOF && c != ' ' && c != '\n') { v *= 10; v += c - '0'; } return v * sign; }
inline string readstring() { string s; char c; while ((c = getchar()) != EOF && c != '\n' && c != ' ') { s.push_back(c); } return s; }
template <class result_t=std::chrono::milliseconds,class clock_t=std::chrono::steady_clock,class duration_t = std::chrono::milliseconds>
auto since(std::chrono::time_point<clock_t, duration_t> const& start){return std::chrono::duration_cast<result_t>(clock_t::now() - start);}
typedef pair<int, int> pii;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpii;
typedef vector<pl> vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<vpii> vvpii;
typedef vector<vpl> vvpl;



struct Node{
    Node *lnode = 0, *rnode;
    int l, r;
    pl val = {INF, -1};
    pl val2 = {INF, -1};
    Node(int l, int r) : l(l), r(r){}

    pl query(int lo, int hi, pl &exclude){
        if(r <= lo || hi <= l) return {INF, -1};
        if(r <= hi && lo <= l) return (val == exclude?val2:val);
        push();
        return min(lnode->query(lo, hi, exclude), rnode->query(lo, hi, exclude));
    }

    void update(int x, int start, int index){
        if(r<=x || l>x) return;
        if(r-l == 1) {
            val2 = min(val2, {start, index});
            if(val>val2)swap(val, val2);
            return;
        }
        push();
        lnode->update(x, start, index);
        rnode->update(x, start, index);
        val = min(lnode->val, rnode->val);
        val2 = min(max(lnode->val, rnode->val), min(lnode->val2, rnode->val2));
    }

    void push(){
        if(!lnode){
            int mid = (l+r) / 2;
            lnode = new Node(l, mid);
            rnode = new Node(mid, r);
        }
    }
};

int main() {
    // cout << fixed << setprecision(20);
    // auto start = std::chrono::steady_clock::now(); // since(start).count()
    cin.tie(0)->sync_with_stdio(0);

    ll n, q, from, to;
    cin >> n >> q;

    Node st(0, INF);
    vpl event;
    
    fo(i, n){
        cin >> from >> to;
        event.pb({from, to});
        st.update(to, from, i);
    }
    vvl bl(n, vl(25, -1));
    fo(i, n){
        bl[i][0] = i;
        pl current = {event[i].F, i};
        pl res = st.query(event[i].F, event[i].S+1, current);
        if(res.S != -1) bl[i][0] = res.S;
    }
    fo(j, 23){
        fo(i, n)
            bl[i][j+1] = bl[bl[i][j]][j];
    }
    



    fo(x, q){
        cin >> from >> to;
        from--;
        to--;
        if(from == to){
            cout << "0\n";
            continue;
        }
        if(event[from].S<=event[to].S && event[from].S>=event[to].F){
            cout << "1\n";
            continue;
        }
        int ans = 2;
        for(int i = 21; i>=0; i--){
            if(event[bl[to][i]].F<=event[from].S) continue;
            ans+=(1<<i);
            to = bl[to][i];
        }
        to = bl[to][0];
        if(event[from].S<=event[to].S && event[from].S>=event[to].F)
            cout << ans << "\n";
        else cout << "impossible\n";
    }

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 30 / 30