Submission #472025

#	Time	Username	Problem	Language	Result	Execution time	Memory
472025		hidden1	Senior Postmen (BOI14_postmen)	C++14	100 / 100	478 ms	42116 KiB

postmen

#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC target ("sse4")
#define endl "\n"
typedef long long ll;
template<class T, class T2> inline ostream &operator <<(ostream &out, const pair<T, T2> &x) { out << x.first << " " << x.second; return out;}
template<class T, class T2> inline istream &operator >>(istream &in, pair<T, T2> &x) { in >> x.first >> x.second; return in;}
template<class T, class T2> inline bool chkmax(T &x, const T2 &y) { return x < y ? x = y, 1 : 0; }
template<class T, class T2> inline bool chkmin(T &x, const T2 &y) { return x > y ? x = y, 1 : 0; }
const ll mod = 1e9 + 7;
#define out(x) "{" << (#x) << ": " << x << "} "

const int MAX_N = 5e5 + 10;
vector<pair<int, int> > g[MAX_N];
bool used[MAX_N];
int n, m;
vector<int> ans;
int cnt[MAX_N];
bool in[MAX_N];

void dfs(int x) {
    stack<int> st;
    st.push(x);
    while(!st.empty()) {
        auto curr = st.top();
        int got = -1;
        for(; cnt[curr] < g[curr].size();) {
            auto it = g[curr][cnt[curr] ++];
            if(used[it.second]) {continue;}
            used[it.second] = true;
            got = it.first;
            break;
        }
        if(got == -1) {
            ans.push_back(curr);
            st.pop();
        } else {
            st.push(got);
        }
    }
}

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    cin >> n >> m;
    for(int i = 0; i < m; i ++) {
        int a, b;
        cin >> a >> b;
        g[a].push_back({b, i});
        g[b].push_back({a, i});
    }
    for(int i = 1; i <= n; i ++) {
        if(cnt[i] != g[i].size()) {
            dfs(i);
        }
    }
    stack<int> st;
    for(auto it : ans) {
        if(in[it]) {
            cout << it << " ";
            while(st.top() != it) {
                cout << st.top() << " ";
                in[st.top()] = false;
                st.pop();
            }
            cout << endl;
        } else {
            st.push(it);
            in[it] = true;
        }
    }
    return 0;
}

Compilation message (stderr)

postmen.cpp: In function 'void dfs(int)':
postmen.cpp:28:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |         for(; cnt[curr] < g[curr].size();) {
      |               ~~~~~~~~~~^~~~~~~~~~~~~~~~
postmen.cpp: In function 'int main()':
postmen.cpp:54:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |         if(cnt[i] != g[i].size()) {
      |            ~~~~~~~^~~~~~~~~~~~~~

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