Submission #1046392

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046392		xnqs	Cheap flights (LMIO18_pigus_skrydziai)	C++17	100 / 100	145 ms	29696 KiB

pigus_skrydziai

#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <set>
#include <unordered_map> 

int gs, edg;
std::vector<std::vector<std::pair<int,int>>> adj_list;
std::vector<std::tuple<int,int,int>> edges;

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);
 
	for (int i = 0, a, b, c; i < edg; i++) {
		std::cin >> a >> b >> c;
		adj_list[a].emplace_back(b,c);
		adj_list[b].emplace_back(a,c);
		edges.emplace_back(std::min(a,b),std::max(a,b),c);
	}
 
	// 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
	std::sort(edges.begin(),edges.end());
	for (int i = 1; i <= gs; i++) {
		std::sort(adj_list[i].begin(),adj_list[i].end(),[](const std::pair<int,int>& a, const std::pair<int,int>& b) {
			return a.second > b.second;
		});
		if (adj_list[i].size()>=2) {
			auto [a, wa] = adj_list[i][0];
			auto [b, wb] = adj_list[i][1];

			auto it = std::lower_bound(edges.begin(),edges.end(),std::tuple<int,int,int>(std::min(a,b),std::max(a,b),0));
			if (it!=edges.end()&&std::get<0>(*it)==std::min(a,b)&&std::get<1>(*it)==std::max(a,b)) {
				ans = std::max(ans, (int64_t)wa + wb + std::get<2>(*it));
			}
		}
	}
 
	std::cout << ans << "\n";
}

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