Submission #633897

#	Time	Username	Problem	Language	Result	Execution time	Memory
633897		Do_you_copy	Senior Postmen (BOI14_postmen)	C++17	0 / 100	2 ms	2684 KiB

postmen

#include <bits/stdc++.h>
//#define int long long
#define fi first
#define se second
#define pb push_back
#define faster ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
using ll = long long;
using ull = unsigned ll;
using ld = long double;
using pii = pair <int, int>;
using pil = pair <int, ll>;
using pli = pair <ll, int>;
using pll = pair <ll, ll>;
mt19937 Rand(chrono::steady_clock::now().time_since_epoch().count());

ll min(const ll &a, const ll &b){
    return (a < b) ? a : b;
}

ll max(const ll &a, const ll &b){
    return (a > b) ? a : b;
}

//const ll Mod = 1000000007;
//const ll Mod2 = 999999999989;
//only use when required
const int maxN = 1e5 + 1;
int n, m;

vector <pii> adj[maxN];
int cur[maxN];
bool visited[maxN];
bool vis[maxN];
int cycle;
vector <vector <int>> ans;

void dfs(int u, int p){
    for (; cur[u] < adj[u].size(); ++cur[u]){
        pii i = adj[u][cur[u]];
        int v = i.fi;
        if (v == p || vis[i.se]) continue;
        visited[u] = 1;
        vis[i.se] = 1;
        if (visited[v]){
            cycle = v;
            ans.pb({u});
            visited[u] = 0;
            return;
        }
        //if (u == 3) cerr << v << "!";
        dfs(v, u);
        if (cycle){
            ans.back().pb(u);
            visited[u] = 0;
            if (cycle != u) return;
            else{
                cycle = 0;
            }
        }
    }
}

void Init(){
    cin >> n >> m;
    for (int i = 1; i <= m; ++i){
        int u, v;
        cin >> u >> v;
        adj[u].pb({v, i});
        adj[v].pb({u, i});
    }
    for (int i = 1; i <= n; ++i){
        if (cur[i] < adj[i].size())
        dfs(i, 0);
    }
    cout << ans.size() << "\n";
    for (auto &i: ans){
        for (int &j: i) cout << j << " ";
        cout << "\n";
    }
}

#define debu
#define taskname "test"
signed main(){
    if (fopen(taskname".inp", "r")){
        freopen(taskname".inp", "r", stdin);
        #ifdef debug
        freopen(taskname".out", "w", stdout);
        #endif
    }
    faster;
    ll tt = 1;
    //cin >> tt;
    while (tt--){
        Init();
    }
    if (fopen("timeout.txt", "r")){
        ofstream timeout("timeout.txt");
        timeout << 1000 * double(clock()) / CLOCKS_PER_SEC;
        #ifndef debug
        cerr << "\nTime elapsed: " << 1000 * double(clock()) / CLOCKS_PER_SEC << "ms\n";
        #endif
    }
}

Compilation message (stderr)

postmen.cpp: In function 'void dfs(int, int)':
postmen.cpp:39:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |     for (; cur[u] < adj[u].size(); ++cur[u]){
      |            ~~~~~~~^~~~~~~~~~~~~~~
postmen.cpp: In function 'void Init()':
postmen.cpp:73:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |         if (cur[i] < adj[i].size())
      |             ~~~~~~~^~~~~~~~~~~~~~~
postmen.cpp: In function 'int main()':
postmen.cpp:87:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   87 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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