Submission #1119662

#	Time	Username	Problem	Language	Result	Execution time	Memory
1119662		vjudge1	Senior Postmen (BOI14_postmen)	C++17	100 / 100	493 ms	86248 KiB

postmen

#include<bits/stdc++.h>
using namespace std;
#define task "task"
#define ii pair<int,int>
#define fi first
#define se second
#define int long long
#define ll long long
#define ld double
#define mp make_pair
#define lg2 30
#define iii pair<int,ii>
#define iiii pair<ii,ii>
#define fii fi.fi
#define fis fi.se3
#define sfi se.fi
#define see se.se
#define base 29
int dx[]={0LL,0LL,1,-1,1,1,-1,-1};
int dy[]={1,-1,0LL,0LL,1,-1,1,-1};
const int maxn=1e6+1;
const int mod=1e9+7;
int n,in[maxn],out[maxn],m,used_edge[maxn];
vector<int>ans;
vector<ii>a[maxn];
list<int> euler_walk(int u) {
    list<int> ans;
    ans.push_back(u);
    while (!a[u].empty()) {
        int v = a[u].back().fi;
        int eid = a[u].back().se;
        a[u].pop_back();
        if (used_edge[eid]) continue;
        used_edge[eid] = true;
        u = v;
        ans.push_back(u);
    }
    for (auto it = ++ans.begin(); it != ans.end(); ++it) {
        auto t = euler_walk(*it);
        t.pop_back();
        ans.splice(it, t);
    }
    return ans;
}
int pos[maxn];
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    if(fopen(task".inp","r")){
    freopen(task".inp","r",stdin);
    freopen(task".out","w",stdout);}
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int u,v;
        cin>>u>>v;
        a[u].push_back({v,i});
        a[v].push_back({u,i});
    }
    list<int>ans=euler_walk(1);
 //   for(int x:ans)cout<<x<<" ";
   // cout<<'\n';
    stack<int>s;
    for(auto x:ans)
    {
        if(pos[x]==0)pos[x]=1;
        else
        {
            while(true)
            {
                int t=s.top();s.pop();
                pos[t]=0;
                cout<<t<<" ";
                if(t==x)break;
            }
            cout<<'\n';
        }
        pos[x]=1;
        s.push(x);
    }
    cerr <<endl<< "TIME : " << clock() * 0.001 << "s" << endl ;
}

Compilation message (stderr)

postmen.cpp: In function 'int main()':
postmen.cpp:50:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |     freopen(task".inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
postmen.cpp:51:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |     freopen(task".out","w",stdout);}
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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