Submission #613808

#	Time	Username	Problem	Language	Result	Execution time	Memory
613808		andrei_boaca	007 (CEOI14_007)	C++14	0 / 100	1097 ms	20280 KiB

007

#include <bits/stdc++.h>

using namespace std;
int n,m,s,d,a,b;
vector<int> muchii[200005];
int dist[6][200005];
bool use[200005];
void bfs(int start,int index)
{
    for(int i=1;i<=n;i++)
        dist[index][i]=1e9;
    dist[index][start]=0;
    queue<int> coada;
    coada.push(start);
    while(!coada.empty())
    {
        int nod=coada.front();
        coada.pop();
        for(int i:muchii[nod])
            if(dist[index][i]>dist[index][nod]+1)
            {
                dist[index][i]=dist[index][nod]+1;
                coada.push(i);
            }
    }
}
void dfs(int nod,int bad)
{
    use[nod]=1;
    for(int i:muchii[nod])
        if(!use[i]&&i!=bad)
            dfs(i,bad);
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>m>>s>>d>>a>>b;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        cin>>x>>y;
        muchii[x].push_back(y);
        muchii[y].push_back(x);
    }
    bfs(a,1);
    bfs(b,2);
    bfs(d,3);
    bfs(s,4);
    int minim=1e9;
    for(int i=1;i<=n;i++)
    {
        bool good;
        if((dist[1][i]+1>=dist[1][s]&&dist[2][i]+1>=dist[2][s])||dist[4][i]<=1)
            good=1;
        else
        {
            bfs(i,5);
            good=0;
            for(int j=1;j<=n;j++)
                if(j!=i)
                {
                    for(int k=1;k<=n;k++)
                        use[k]=0;
                    dfs(i,j);
                    if(use[a]||use[b])
                        continue;
                    if(dist[4][j]<=dist[5][j]+1)
                        good=1;
                    break;
                }
        }
        if(!good)
            minim=min(minim,dist[3][i]-2);
    }
    cout<<max(-1,minim);
    return 0;
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 70