Submission #1046341

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046341		xnqs	Cheap flights (LMIO18_pigus_skrydziai)	C++17	28 / 100	3074 ms	49604 KiB

pigus_skrydziai

#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <set>
 
int gs, edg;
std::vector<std::set<std::pair<int,int>>> adj_list;
 
int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(NULL);
	std::cout.tie(NULL);
 
	std::cin >> gs >> edg;
	adj_list.resize(gs+1);
 
	std::priority_queue<int> q;
	for (int i = 0, a, b, c; i < edg; i++) {
		std::cin >> a >> b >> c;
		adj_list[a].emplace(b,c);
		adj_list[b].emplace(a,c);
		q.emplace(c);
	}
 
	int64_t max_tri = 0;
	for (int cnt = 0; !q.empty() && cnt < 3; cnt++) {
		max_tri += q.top();
		q.pop();
	}
 
	// try all star graphs
	int64_t ans = 0;
	for (int i = 1; i <= gs; i++) {
		int64_t cand = 0;
		for (const auto& [j, w] : adj_list[i]) {
			cand += w;
		}
		ans = std::max(ans,cand);
	}
 
	// try all "triangle" cycles
	if (ans<=max_tri)
	for (int i = 1; i <= gs; i++) {
		if (adj_list[i].size()>300) {
			continue;
		}
		for (const auto& [j, wj] : adj_list[i]) {
			if (j<i) {
				continue;
			}
			for (const auto& [k, wk] : adj_list[j]) {
				if (k<j) {
					continue;
				}
				if (k==i) {
					continue;
				}
 
				auto it = adj_list[k].lower_bound(std::pair<int,int>(i,0));
				if (it!=adj_list[k].end()&&it->first==i) {
					//std::cout << i << " " << j << " " << k << "\n";
					//std::cout << wj << " " << wk << " " << it->second << "\n";
					ans = std::max(ans, static_cast<int64_t>(wj)+wk+it->second);
				}
			}
		}
	}
 
	std::cout << ans << "\n";
}

• Subtask 1: 12 / 12
• Subtask 2: 0 / 25
• Subtask 3: 16 / 16
• Subtask 4: 0 / 47