Submission #748878

#	Time	Username	Problem	Language	Result	Execution time	Memory
748878		GrindMachine	Event Hopping (BOI22_events)	C++17	0 / 100	1567 ms	1116 KiB

events

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

void solve(int test_case)
{
    int n,q; cin >> n >> q;
    vector<pii> a(n+5);
    rep1(i,n) cin >> a[i].ff >> a[i].ss;

    while(q--){
        int u,v; cin >> u >> v;
        vector<bool> vis(n+5);
        ll ans = 0;

        while(u != v){
            ans++;
            vis[u] = 1;

            ll nxt = -1;
            ll mxe = -1;

            rep1(j,n){
                if(j == u) conts;

                auto [si,ei] = a[u];
                auto [sj,ej] = a[j];

                if(sj <= ei and ei <= ej){
                    if(j == v){
                        nxt = j;
                        break;
                    }

                    if(ej > mxe){
                        mxe = ej;
                        nxt = j;
                    }
                }
            }

            if(nxt == -1 or vis[nxt]) {
                ans = -1;
                break;
            }

            u = nxt;
        }

        if(ans != -1){
            cout << ans << endl;
        }
        else{
            cout << "impossible" << endl;
        }
    }
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30