Submission #419638

#	Time	Username	Problem	Language	Result	Execution time	Memory
419638		VladM	Senior Postmen (BOI14_postmen)	C++14	55 / 100	585 ms	125000 KiB

postmen

#include <bits/stdc++.h>

using namespace std;

#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")

#define DIM 500007

int u, v, n, m, par[DIM], vis[DIM];

set<int> vec[DIM];

void dfs(int v)
{
    vis[v]=1;
    for(auto to : vec[v])
    {
        if(to==par[v]) continue;
        if(vis[to]==1)
        {
            vec[v].erase(to);
            vec[to].erase(v);
            while(v!=to)
            {
                int p=par[v];
                printf("%d ", v);
                vec[v].erase(p);
                vec[p].erase(v);
                vis[v]=0;
                par[v]=0;
                v=p;
            }
            printf("%d\n", v);
            if(!vec[v].empty()) dfs(v);
        }
        else
        {
            par[to]=v;
            dfs(to);
        }
        break;
    }
    return;
}

int main()
{
    scanf("%d%d", &n, &m);
    for(int i=1; i<=m; i++)
    {
        scanf("%d%d", &u, &v);
        if(vec[v].find(u)!=vec[v].end())
        {
            printf("%d %d\n", u, v);
            vec[u].erase(v);
            vec[v].erase(u);
        }
        else
        {
            vec[u].insert(v);
            vec[v].insert(u);
        }
    }
    for(int i=1; i<=n; i++)
    {
        if(vec[i].size()!=0)
        {
            dfs(i);
        }
    }
    return 0;
}

Compilation message (stderr)

postmen.cpp:6: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    6 | #pragma GCC optimization ("O3")
      | 
postmen.cpp:7: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    7 | #pragma GCC optimization ("unroll-loops")
      | 
postmen.cpp: In function 'int main()':
postmen.cpp:50:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
postmen.cpp:53:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |         scanf("%d%d", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~

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