Submission #545857

#	Time	Username	Problem	Language	Result	Execution time	Memory
545857		stefantaga	Torrent (COI16_torrent)	C++14	31 / 100	2045 ms	29004 KiB

torrent

#include <bits/stdc++.h>

using namespace std;
vector <pair <int,int>> v[300005];
pair <int,int > tata[300005];
int mar[300005];
void dfs(int x,int dad)
{
    mar[x]=1;
    for (int i=0;i<v[x].size();i++)
    {
        int nod = v[x][i].first;
        if (nod!=dad)
        {
            tata[nod]={x,v[x][i].second};
            dfs(nod,x);
            mar[x]+=mar[nod];
        }
    }
}
int din[300005];
void dfssol(int x,int muchie_interzisa,int dad)
{
    int i,nr=1;
    for (int i=0;i<v[x].size();i++)
    {
        int nod = v[x][i].first;
        if (nod!=dad&&v[x][i].second!=muchie_interzisa)
        {
            dfssol(nod,muchie_interzisa,x);
            din[x]=max(din[x],din[nod]+nr);
            nr++;
        }
    }
}
bool compare2 (pair <int,int> a,pair <int,int> b )
{
    return mar[a.first]>mar[b.first];
}
int n,a,b,i,j,k;
vector <int> muchii;
int main()
{
    ios_base :: sync_with_stdio(false);
    cin.tie(0);
    #ifdef HOME
    ifstream cin("date.in");
    ofstream cout("date.out");
    #endif // HOME
    cin>>n>>a>>b;
    for (i=1;i<=n-1;i++)
    {
        int x,y;
        cin>>x>>y;
        v[x].push_back({y,i});
        v[y].push_back({x,i});
    }
    dfs(a,0);
    for (i=1;i<=n;i++)
    {
        sort(v[i].begin(),v[i].end(),compare2);
    }
    int cop = b;
    while (cop!=a)
    {
        muchii.push_back(tata[cop].second);
        cop=tata[cop].first;
    }
    int minim = 1e9;
    for (j=0;j<muchii.size();j++)
    {
        for (k=1;k<=n;k++)
        {
            din[k]=0;
        }
        dfssol(a,muchii[j],0);
        dfssol(b,muchii[j],0);
        minim=min(minim,max(din[a],din[b]));
    }
    cout<<minim;
    return 0;
}

Compilation message (stderr)

torrent.cpp: In function 'void dfs(int, int)':
torrent.cpp:10:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |     for (int i=0;i<v[x].size();i++)
      |                  ~^~~~~~~~~~~~
torrent.cpp: In function 'void dfssol(int, int, int)':
torrent.cpp:25:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |     for (int i=0;i<v[x].size();i++)
      |                  ~^~~~~~~~~~~~
torrent.cpp:24:9: warning: unused variable 'i' [-Wunused-variable]
   24 |     int i,nr=1;
      |         ^
torrent.cpp: In function 'int main()':
torrent.cpp:70:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |     for (j=0;j<muchii.size();j++)
      |              ~^~~~~~~~~~~~~~

• Subtask 1: 31 / 31
• Subtask 2: 0 / 69