Submission #1119684

#	Time	Username	Problem	Language	Result	Execution time	Memory
1119684		vjudge1	Senior Postmen (BOI14_postmen)	C++17	55 / 100	510 ms	59604 KiB

postmen

#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
const int maxn = 5e5 + 5;
int n, m;
vector<vector<pair<int, int>>> g;
vector<int> path;
vector<bool> seen;
bool vs[maxn];
void dfs(int node) {
	while (!g[node].empty()) {
	    int son = g[node].back().fi, idx = g[node].back().se;
//		auto [son, idx] = g[node].back();
		g[node].pop_back();
		if (seen[idx]) { continue; }
		seen[idx] = true;
		dfs(son);
	}
	path.push_back(node);
}

int main() {
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//	freopen("main.inp", "r", stdin);
	cin >> n >> m;
	g.resize(n+1);
	seen.resize(m+1);

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

    dfs(1);
    // for (int x : path) cout << x << " ";
    // cout << endl;
    stack<int> st;
    for (int i = 0; i < path.size(); i++) {
        if (vs[path[i]]) {
            while(!st.empty() && st.top() != path[i]) {
            	cout << st.top() << " ";
            	vs[st.top()] = 0;
                st.pop();
            } 
            cout << st.top() << " ";
            st.pop();
            cout << endl;
        }
        st.push(path[i]);
        vs[path[i]] = 1;
    }
}

Compilation message (stderr)

postmen.cpp: In function 'int main()':
postmen.cpp:41:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |     for (int i = 0; i < path.size(); i++) {
      |                     ~~^~~~~~~~~~~~~

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