Submission #850162

#	Time	Username	Problem	Language	Result	Execution time	Memory
850162		NK_	Ball Machine (BOI13_ballmachine)	C++17	100 / 100	160 ms	29128 KiB

ballmachine

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
 
using namespace std;
 
#define nl '\n'
#define pb push_back
#define pf push_front
 
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
 
template<class T> using V = vector<T>;
using pi = pair<int, int>;
using vi = V<int>;
using vpi = V<pi>;
 
using ll = long long;
using pl = pair<ll, ll>;
using vpl = V<pl>;
using vl = V<ll>;
 
using db = long double;
 
template<class T> using pq = priority_queue<T, V<T>, greater<T>>;
 
const int MOD = 1e9 + 7;
const ll INFL = ll(1e17);
const int LG = 18;

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

	int N, Q; cin >> N >> Q;

	int R = -1;
	vi P(N);
	V<vi> chd(N); for(int i = 0; i < N; i++) {
		int p; cin >> p; --p;
		if (p != -1) chd[p].pb(i), P[i] = p;
		else R = i, P[i] = -1;
	}

	vi mn(N, MOD), dep(N);
	V<vi> up(N+1, vi(LG, N));
	function<void(int)> gen = [&](int u) {
		for(int i = 1; i < LG; i++) up[u][i] = up[up[u][i-1]][i-1];

		mn[u] = u;
		for(auto& v : chd[u]) {
			up[v][0] = u; dep[v] = dep[u] + 1; gen(v);
			mn[u] = min(mn[v], mn[u]);
		}

	};

	dep[R] = 0; gen(R);

	vi deg(N); for(int i = 0; i < N; i++) deg[i] = sz(chd[i]);

	vi ord(N); int cur = 0;

	function<void(int)> dfs = [&](int u) {
		sort(begin(chd[u]), end(chd[u]), [&](int x, int y) {
			return mn[x] < mn[y];
		});

		for(auto v : chd[u]) dfs(v);

		ord[u] = cur++;
	};
	dfs(R);
 		
 	pq<pi> W; for(int i = 0; i < N; i++) W.push(mp(ord[i], i));

 	vi C(N+1); // C[i] = 0 (off) / 1 (on)
 	for(int t = 0; t < Q; t++) {
 		int type; cin >> type;
 		if (type == 1) {
 			int k; cin >> k;
 			int lst = -1;
 			while(k--) {
 				int u = W.top().s; W.pop();
 				// cout << "ADD: " << u << endl;
 				C[u] = 1; lst = u; 
 			}
 			cout << lst + 1 << nl;
 		} else {
 			int u; cin >> u; --u;
 			int d = dep[u];

 			assert(C[u] == 1);
 			for(int i = LG-1; i >= 0; i--) {
 				// cout << u << " " << i << endl;
 				// cout << up[u][i] << endl;
 				if (C[up[u][i]]) u = up[u][i];
 			}


 			// cout << "REM: " << u << endl;

 			C[u] = 0; if (u != N) W.push(mp(ord[u], u));
 			cout << d - dep[u] << nl;
 		}
 	}

 	// for(int i = 0; i < N; i++) cout << i << " " << C[i] << endl;


	exit(0-0);
} 

• Subtask 1: 25 / 25
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40
• Subtask 4: 5 / 5