結果

問題 No.1833 Subway Planning
ユーザー kaikeykaikey
提出日時 2022-02-04 23:03:42
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 563 ms / 4,000 ms
コード長 4,753 bytes
コンパイル時間 2,322 ms
コンパイル使用メモリ 228,060 KB
実行使用メモリ 35,000 KB
最終ジャッジ日時 2024-06-11 12:41:13
合計ジャッジ時間 10,155 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge1
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
5,248 KB
testcase_01 AC 2 ms
5,376 KB
testcase_02 AC 2 ms
5,376 KB
testcase_03 AC 2 ms
5,376 KB
testcase_04 AC 179 ms
34,872 KB
testcase_05 AC 257 ms
34,872 KB
testcase_06 AC 244 ms
35,000 KB
testcase_07 AC 500 ms
34,868 KB
testcase_08 AC 509 ms
34,872 KB
testcase_09 AC 494 ms
34,876 KB
testcase_10 AC 248 ms
25,148 KB
testcase_11 AC 250 ms
25,144 KB
testcase_12 AC 212 ms
25,148 KB
testcase_13 AC 221 ms
25,144 KB
testcase_14 AC 206 ms
26,680 KB
testcase_15 AC 277 ms
26,676 KB
testcase_16 AC 281 ms
29,076 KB
testcase_17 AC 563 ms
26,744 KB
testcase_18 AC 554 ms
25,136 KB
testcase_19 AC 301 ms
25,980 KB
testcase_20 AC 246 ms
20,820 KB
testcase_21 AC 393 ms
31,552 KB
testcase_22 AC 362 ms
28,372 KB
testcase_23 AC 1 ms
5,376 KB
testcase_24 AC 2 ms
5,376 KB
testcase_25 AC 1 ms
5,376 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include "bits/stdc++.h"
#include <random>
#include <chrono>
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define SZ(x) ((lint)(x).size())
#define FOR(i, begin, end) for(lint i=(begin),i##_end_=(end);i<i##_end_;++i)
#define IFOR(i, begin, end) for(lint i=(end)-1,i##_begin_=(begin);i>=i##_begin_;--i)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
#define endk '\n'
using namespace std; typedef unsigned long long _ulong; typedef long long int lint; typedef long double ld; typedef pair<lint, lint> plint; typedef pair<ld, ld> pld;
struct fast_ios { fast_ios() { cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(10); }; } fast_ios_;
template<class T> auto add = [](T a, T b) -> T { return a + b; };
template<class T> auto mul = [](T a, T b) -> T { return a * b; };
template<class T> auto f_max = [](T a, T b) -> T { return max(a, b); };
template<class T> auto f_min = [](T a, T b) -> T { return min(a, b); };
template<class T> using V = vector<T>;
using Vl = V<lint>; using VVl = V<Vl>; using VVVl = V<V<Vl>>;
template< typename T > ostream& operator<<(ostream& os, const vector< T >& v) {
	for (int i = 0; i < (int)v.size(); i++) os << v[i] << (i + 1 != v.size() ? " " : "");
	return os;
}
template< typename T >istream& operator>>(istream& is, vector< T >& v) {
	for (T& in : v) is >> in;
	return is;
}
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; }
template <class T>
T div_floor(T a, T b) {
	if (b < 0) a *= -1, b *= -1;
	return a >= 0 ? a / b : (a + 1) / b - 1;
}
template <class T>
T div_ceil(T a, T b) {
	if (b < 0) a *= -1, b *= -1;
	return a > 0 ? (a - 1) / b + 1 : a / b;
}
template <class F> struct rec {
	F f;
	rec(F&& f_) : f(std::forward<F>(f_)) {}
	template <class... Args> auto operator()(Args &&... args) const {
		return f(*this, std::forward<Args>(args)...);
	}
};
lint gcd(lint a, lint b) { if (b == 0) return a; else return gcd(b, a % b); }
lint digit(lint a) { return (lint)log10(a); }
lint e_dist(plint a, plint b) { return abs(a.first - b.first) * abs(a.first - b.first) + abs(a.second - b.second) * abs(a.second - b.second); }
lint m_dist(plint a, plint b) { return abs(a.first - b.first) + abs(a.second - b.second); }
bool check_overflow(lint a, lint b, lint limit) { if (b == 0) return false; return a >= limit / b; } // a * b > c => true
void Worshall_Floyd(VVl& g) { REP(k, SZ(g)) REP(i, SZ(g)) REP(j, SZ(g)) chmin(g[i][j], g[i][k] + g[k][j]); }
const lint MOD1000000007 = 1000000007, MOD998244353 = 998244353, INF = 2e18;
lint dx[8] = { 0, -1, 0, 1, 1, -1, 1, -1 }, dy[8] = { -1, 0, 1, 0, -1, -1, 1, 1 };
bool YN(bool flag) { cout << (flag ? "YES" : "NO") << endk; return flag; } bool yn(bool flag) { cout << (flag ? "Yes" : "No") << endk; return flag; }
struct Edge {
	lint from, to;
	lint cost;
	Edge() {

	}
	Edge(lint u, lint v, lint c) {
		cost = c;
		from = u;
		to = v;
	}
	bool operator<(const Edge& e) const {
		return cost < e.cost;
	}
};
struct WeightedEdge {
	lint to;
	lint cost;
	WeightedEdge(lint v, lint c = 1) {
		to = v;
		cost = c;
	}
	bool operator<(const WeightedEdge& e) const {
		return cost < e.cost;
	}
};
using WeightedGraph = V<V<WeightedEdge>>;
typedef pair<lint, plint> tlint;
typedef pair<ld, ld> pld;
typedef pair<plint, plint> qlint;
typedef pair<string, lint> valstr;
typedef pair<Vl, lint> valv;

int main() {
	lint N;
	cin >> N;
	V<tlint> ed;
	WeightedGraph g(N);
	REP(i, N - 1) {
		lint u, v, c;
		cin >> u >> v >> c; u--; v--;
		g[u].push_back({ v, c });
		g[v].push_back({ u, c });
		ed.push_back({ c, {u, v} });
	}

	auto check = [&](lint val) {
		Vl need(N);
		lint root = -1;
		REP(i, N - 1) {
			lint u = ed[i].second.first, v = ed[i].second.second, c = ed[i].first;
			if (c <= val) continue;
			need[u] = 1;
			need[v] = 1;
			root = u;
		}
		if (root == -1) return true;

		Vl deg(N);
		lint maxv = 0, minv = INF;
		auto dfs = [&](auto&& dfs, lint curr, lint prv) -> bool {
			bool flag = false;
			if (need[curr]) flag = true;
			for (auto e : g[curr]) {
				if (prv == e.to) continue;
				bool res = dfs(dfs, e.to, curr);
				if (res) {
					chmax(maxv, e.cost);
					chmin(minv, e.cost);
					deg[e.to]++;
					deg[curr]++;
				}
				flag |= res;
			}
			return flag;
		};

		dfs(dfs, root, -1);
		sort(ALL(deg));
		map<lint, lint> cnt;
		REP(i, N) cnt[deg[i]]++;
		return cnt[0] + cnt[1] + cnt[2] == N && cnt[1] == 2 && maxv - minv <= val;
	};

	lint ng = -1, ok = 1e9 + 1;
	while (ok - ng > 1) {
		lint mid = (ok + ng) / 2;
		if (check(mid)) ok = mid;
		else ng = mid;
	}
	cout << ok << endl;
}
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