Cod sursa(job #1326633)

Utilizator margikiMargeloiu Andrei margiki Data 25 ianuarie 2015 19:30:22
Problema Stramosi Scor 80
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.01 kb
# include <fstream>
# include <algorithm>
# include <vector>
# define N 250005
# define M 300005
using namespace std;
ifstream f("stramosi.in");
ofstream g("stramosi.out");
vector <int> v[N];
struct elem
{
    int ord, q;
}E;
vector <elem> querry[M];
int i,j,n,m,x,y,VV;
int st[N], sol[M];
bool in[N], ap[N];
void DFS (int k)
{
    ap[k]=1;
    st[++VV]=k;
    for (int i=0; i<querry[k].size(); ++i)
    {
        int S=0, var=querry[k][i].q;
        if (var>=VV) S=0;
        else S=st[VV-var];
        sol[querry[k][i].ord]=S;
    }
    for (int i=0; i<v[k].size(); ++i)
        if (! ap[v[k][i]]) DFS(v[k][i]);
    --VV;
}
int main ()
{
    f>>n>>m;
    for (i=1; i<=n; ++i)
    {
        f>>x; v[x].push_back(i);
        if (x!=0) in[i]=1;
    }
    for (i=1; i<=m; ++i)
    {
        f>>x>>y;
        E.ord=i; E.q=y;
        querry[x].push_back(E);
    }

    for (i=1; i<=n; ++i)
        if (! in[i]) DFS(i);

    for (i=1; i<=m; ++i)
        g<<sol[i]<<"\n";

    return 0;
}