제출 #1075007

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1075007		42kangaroo	통행료 (IOI18_highway)	C++17	100 / 100	212 ms	24268 KiB

highway

//
// Created by 42kangaroo on 25/08/2024.
//
#include "bits/stdc++.h"
#include "highway.h"

using ll = long long;

using namespace std;
struct Ed {
	int to, i;
};
using g_t = vector<vector<Ed>>;

struct BfsVal {
	int to, i, d;
};

bool operator<(const BfsVal &l, const BfsVal &r) {
	return l.d < r.d;
}

void addDfs(int n, int p, g_t &g, vector<int> &dis, vector<BfsVal> &out) {
	for (auto e: g[n]) {
		if (e.to == p) continue;
		out.push_back({e.to, e.i, dis[e.to]});
		addDfs(e.to, n, g, dis, out);
	}
}

void wDfs(int n, int p, g_t &g, vector<int> &w) {
	for (auto e: g[n]) {
		if (e.to == p) continue;
		w[e.i] = 0;
		wDfs(e.to, n, g, w);
	}
}

void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
	vector<int> w(U.size(), 0);
	ll le = ask(w) / (ll) A;
	vector<bool> vis(N, false);
	g_t g(N);
	for (int i = 0; i < U.size(); ++i) {
		g[U[i]].push_back({V[i], i});
		g[V[i]].push_back({U[i], i});
	}
	int l = 0, r = U.size();
	while (l + 1 < r) {
		int m = (l + r) / 2;
		std::fill(w.begin(), w.end(), 1);
		for (int i = 0; i < m; ++i) {
			w[i] = 0;
		}
		if (ask(w) > le * A) l = m;
		else r = m;
	}
	vector<int> dis(N, -1);
	g_t gBfs(N);
	queue<BfsVal> q;
	q.push({U[l], -1, 0});
	q.push({V[l], -1, 0});
	while (!q.empty()) {
		auto bfV = q.front();
		q.pop();
		if (dis[bfV.to] != -1) continue;
		if (bfV.i >= 0) {
			gBfs[U[bfV.i]].push_back({V[bfV.i], bfV.i});
			gBfs[V[bfV.i]].push_back({U[bfV.i], bfV.i});
		}
		dis[bfV.to] = bfV.d;
		for (auto e: g[bfV.to]) {
			q.push({e.to, e.i, bfV.d + 1});
		}
	}
	vector<BfsVal> out;
	int x = U[l], y = V[l];
	addDfs(U[l], V[l], gBfs, dis, out);
	out.push_back({U[l], l, 0});
	std::sort(out.begin(), out.end());
	int ll = 0, rr = out.size();
	while (ll + 1 < rr) {
		int m = (ll + rr) / 2;
		std::fill(w.begin(), w.end(), 1);
		for (int i = 0; i < m; ++i) {
			w[out[i].i] = 0;
		}
		w[l] = 0;
		wDfs(V[l], U[l], gBfs, w);
		if (ask(w) > A * le) ll = m;
		else rr = m;
	}
	x = out[ll].to;
	out.clear();
	addDfs(V[l], U[l], gBfs, dis, out);
	out.push_back({V[l], l, 0});
	std::sort(out.begin(), out.end());
	ll = 0, rr = out.size();
	while (ll + 1 < rr) {
		int m = (ll + rr) / 2;
		std::fill(w.begin(), w.end(), 1);
		for (int i = 0; i < m; ++i) {
			w[out[i].i] = 0;
		}
		w[l] = 0;
		wDfs(U[l], V[l], gBfs, w);
		if (ask(w) > A * le) ll = m;
		else rr = m;
	}
	y = out[ll].to;
	answer(x, y);
}

컴파일 시 표준 에러 (stderr) 메시지

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:44:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |  for (int i = 0; i < U.size(); ++i) {
      |                  ~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 18 / 18
• Subtask 6: 31 / 31