Submission #31510

#	Time	Username	Problem	Language	Result	Execution time	Memory
31510		cheater2k	Senior Postmen (BOI14_postmen)	C++14	55 / 100	566 ms	44024 KiB

postmen

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

const int N = 500010;

int n, m;
vector < pair<int,int> > G[N];
vector <int> E;
bool del[N];
int pos[N];

inline void dfs(int u) {
	while(!G[u].empty()) {
		int id = G[u].back().first, v = G[u].back().second;
		if (del[id]) { G[u].pop_back(); continue; }
		else del[id] = 1, dfs(v);
	}
	E.push_back(u);
}

int main() {
	//freopen("out.txt", "w", stdout);
	ios_base::sync_with_stdio(false); cin.tie(0);
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= m; ++i) {
		int u, v; scanf("%d%d", &u, &v);
		G[u].push_back(make_pair(i,v));
		G[v].push_back(make_pair(i,u));
	}

	dfs(1);
	//for (int u: E) cerr << u << ' '; cerr << endl;
	stack <int> s;

	for (int i = 0; i < (int)E.size(); ++i) {
		int u = E[i];
		if (!pos[u]) {
			pos[u] = 1;
			s.push(u);
		} else {
			while(s.top() != u) {
				printf("%d ", s.top());
				pos[s.top()] = 0;
				s.pop();
			}
			printf("%d\n", u);
		}
	}
}

Compilation message (stderr)

postmen.cpp: In function 'int main()':
postmen.cpp:24:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~
postmen.cpp:26:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int u, v; scanf("%d%d", &u, &v);
             ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 38 / 38
• Subtask 2: 17 / 17
• Subtask 3: 0 / 45