Submission #488448

#	Time	Username	Problem	Language	Result	Execution time	Memory
488448		ntabc05101	Senior Postmen (BOI14_postmen)	C++17	100 / 100	389 ms	64332 KiB

postmen

#include<bits/stdc++.h>
using namespace std;

#define taskname ""

const int mxN = 500005;

int n, m;
vector< array<int, 2> > adj[mxN];
int nxt[mxN];
bool vis[mxN], used[mxN];

void dfs(int u) {
	if (vis[u]) {
		while (vis[u]) {
			vis[u] = 0;
			cout << 1 + u << " ";
			u = nxt[u];
		}
		cout << "\n";
	}
	while (!adj[u].empty()) {
		auto to = adj[u].back();
		adj[u].pop_back();
		if (!used[to[1]]) {
			used[to[1]] = 1;
			vis[u] = 1;
			nxt[u] = to[0];
			dfs(to[0]);
		}
	}
}

int main() {
	if (fopen(taskname".inp", "r")) {
		freopen(taskname".inp", "r", stdin);
		freopen(taskname".out", "w", stdout);
	}
	else {
		if (fopen(taskname".in", "r")) {
			freopen(taskname".in", "r", stdin);
			freopen(taskname".out", "w", stdout);
		}
	}

	cin.tie(0)->sync_with_stdio(0);

	cin >> n >> m;
	for (int i = 0, x, y; i < m; i++) {
		cin >> x >> y; x--; y--;
		adj[x].push_back({y, i});
		adj[y].push_back({x, i});
	}

	dfs(0);

	return 0;
}

Compilation message (stderr)

postmen.cpp: In function 'int main()':
postmen.cpp:36:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |   freopen(taskname".inp", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
postmen.cpp:37:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |   freopen(taskname".out", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
postmen.cpp:41:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |    freopen(taskname".in", "r", stdin);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
postmen.cpp:42:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |    freopen(taskname".out", "w", stdout);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 38 / 38
• Subtask 2: 17 / 17
• Subtask 3: 45 / 45