Submission #1042891

#	Time	Username	Problem	Language	Result	Execution time	Memory
1042891		42kangaroo	Closing Time (IOI23_closing)	C++17	100 / 100	143 ms	47220 KiB

closing

#include "closing.h"
#include "bits/stdc++.h"

#define ll long long
using namespace std;

struct Ed {
	ll to, w;
};

bool operator<(const Ed &l, const Ed &r) {
	return l.w > r.w;
}

using g_t = vector<vector<Ed>>;

void diDfs(int n, ll d, g_t &g, vector<ll> &di) {
	if (di[n] != -1) return;
	di[n] = d;
	for (auto e: g[n]) {
		diDfs(e.to, d + e.w, g, di);
	}
}

bool markdfs(int n, int p, int y, g_t &g, vector<bool> &ma) {
	if (n == y) return ma[n] = true;
	for (auto e: g[n]) {
		if (e.to == p) continue;
		if (markdfs(e.to, n, y, g, ma)) return ma[n] = true;
	}
	return false;
}

struct Score {
	ll med, mi, nu;
};

bool operator<(const Score& l, const Score& r) {
	return tie(l.med, l.mi) < tie(r.med, r.mi);
}

int max_score(int N, int X, int Y, long long K,
              std::vector<int> U, std::vector<int> V, std::vector<int> W) {
	g_t g(N);
	for (int i = 0; i < N - 1; ++i) {
		g[U[i]].push_back({V[i], W[i]});
		g[V[i]].push_back({U[i], W[i]});
	}
	array<vector<ll>, 2> dist;
	dist.fill(vector<ll>(N, -1));
	diDfs(X, 0, g, dist[0]);
	diDfs(Y, 0, g, dist[1]);
	int nuWithout = 0;
	vector<bool> vis(N, false);
	priority_queue<pair<Ed, bool>> q;
	q.push({{X, 0}, false});
	q.push({{Y, 0}, true});
	ll kC = K;
	while (!q.empty()) {
		auto [ed, com] = q.top();
		q.pop();
		if (vis[ed.to]) continue;
		if (kC < ed.w) break;
		kC -= ed.w;
		nuWithout++;
		vis[ed.to] = true;
		for (auto e: g[ed.to]) {
			q.push({{e.to, dist[com][e.to]}, com});
		}
	}
	vector<bool> ma(N, false);
	markdfs(X, X, Y, g, ma);
	int nuW = 0;
	vector<Score> pos;
	for (int i = 0; i < N; ++i) {
		if (ma[i]) {
			K -= min(dist[0][i], dist[1][i]);
			nuW++;
			if (dist[0][i] == dist[1][i]) nuW++;
			else pos.push_back({2 * (max(dist[0][i], dist[1][i]) - min(dist[0][i], dist[1][i])),
			                    2 * (max(dist[0][i], dist[1][i]) - min(dist[0][i], dist[1][i])), 1});
		} else {
			bool co = dist[0][i] > dist[1][i];
			if (dist[co][i] < dist[!co][i] - dist[co][i]) {
				pos.push_back({2*dist[co][i], 2*dist[co][i], 1});
				pos.push_back({2*(dist[!co][i] - dist[co][i]), 2*(dist[!co][i] - dist[co][i]), 1});
			} else {
				pos.push_back({dist[!co][i], 2*dist[co][i], 2});
			}
		}
	}
	if (K < 0) return nuWithout;
	K *= 2;
	std::sort(pos.begin(), pos.end());
	int laO = 0;
	for (int i = 0; i < pos.size(); ++i) {
		if (pos[i].med*pos[i].nu > K) {
			if (K + laO >= pos[i].med*2 && pos[i].nu == 2) {
				nuW++;
				K -= pos[i].med*2 - laO;
				laO = 0;
			}
			if (pos[i].mi <= K) {
				nuW++;
				K -= pos[i].mi;
			}
		} else {
			if (pos[i].nu == 1) laO = pos[i].med;
			K -= pos[i].med*pos[i].nu;
			nuW+=pos[i].nu;
		}
	}
	return max(nuW, nuWithout);
}

bool workDfs(int n, int p, bool up, g_t& g, int in) {
	if (!up && (in & (1 << n))) return false;
	for (auto e: g[n]) {
		if (e.to == p) continue;
		if (!workDfs(e.to, n, up && (in & (1 << n)), g, in)) return false;
	}
	return true;
}

int max_score2(int N, int X, int Y, long long K,
              std::vector<int> U, std::vector<int> V, std::vector<int> W) {
	g_t g(N);
	for (int i = 0; i < N - 1; ++i) {
		g[U[i]].push_back({V[i], W[i]});
		g[V[i]].push_back({U[i], W[i]});
	}
	array<vector<ll>, 2> dist;
	dist.fill(vector<ll>(N, -1));
	diDfs(X, 0, g, dist[0]);
	diDfs(Y, 0, g, dist[1]);
	int be = 2;
	for (int i = 0; i < 1 << 2*N; ++i) {
		ll su = 0;
		for (int j = 0; j < N; ++j) {
			if ((i & (1 << j)) && (i & (1 << (j + N)))) {
				su += max(dist[0][j], dist[1][j]);
			} else if (i & (1 << j)) su += dist[0][j];
			else if(i & (1 << (j + N))) su += dist[1][j];
		}
		if (su > K) continue;
		if (workDfs(X, X, true, g, i) && workDfs(Y, Y, true, g, i >> N)) be = max(be, __builtin_popcount(i));
	}
	return be;
}

Compilation message (stderr)

closing.cpp: In function 'int max_score(int, int, int, long long int, std::vector<int>, std::vector<int>, std::vector<int>)':
closing.cpp:96:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Score>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   96 |  for (int i = 0; i < pos.size(); ++i) {
      |                  ~~^~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 9 / 9
• Subtask 3: 12 / 12
• Subtask 4: 14 / 14
• Subtask 5: 9 / 9
• Subtask 6: 11 / 11
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 17 / 17