Submission #1113220

#	Time	Username	Problem	Language	Result	Execution time	Memory
1113220		kh0i	Senior Postmen (BOI14_postmen)	C++17	100 / 100	484 ms	89132 KiB

postmen

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

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif

using ll = long long;
using pii = pair<int, int>;

#define F first
#define S second
#define sz(x) (int)((x).size())
#define all(x) (x).begin(), (x).end()

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll get_rand(ll l, ll r) {
    assert(l <= r);
    return uniform_int_distribution<ll> (l, r)(rng);
}

const int N = 5e5 + 3;

int n, m;
vector<pii> g[N];
bool vis[N];
vector<int> path;

void dfs(int u){
    while(!g[u].empty()){
        auto [v, id] = g[u].back();
        g[u].pop_back();
        if(vis[id])
            continue;
        vis[id] = 1;
        dfs(v);
    }
    path.push_back(u);
}

void solve(){
    cin >> n >> m;
    for(int i = 1; i <= m; ++i){
        int u, v;
        cin >> u >> v;
        g[u].emplace_back(v, i);
        g[v].emplace_back(u, i);
    }
    dfs(1);
    debug(path);
    set<int> st;
    vector<int> cur;
    for(int i = 0; i < sz(path) - 1; ++i){
        int u = path[i];
        if(st.count(u)){
            cout << u;
            while(cur.back() != u){
                st.erase(cur.back());
                cout << " " << cur.back();
                cur.pop_back();
            }
            cout << '\n';
        }
        else{
            st.insert(u);
            cur.push_back(u);
        }
    }
    for(int u : cur)
        cout << u << " ";
}

int32_t main() {
    cin.tie(nullptr)->sync_with_stdio(0);
    #define task "troll"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int test = 1;
//    cin >> test;
    for(int i = 1; i <= test; ++i){
//        cout << "Case #" << i << ": ";
        solve();
    }
    #ifdef LOCAL
        cerr << "\n[Time]: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    #endif
    return 0;
}

Compilation message (stderr)

postmen.cpp: In function 'int32_t main()':
postmen.cpp:79:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
postmen.cpp:80:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   80 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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