Cod sursa(job #1588369)

Utilizator RadduFMI Dinu Radu Raddu Data 2 februarie 2016 23:54:44
Problema Stramosi Scor 80
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.99 kb
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f("stramosi.in");
ofstream g("stramosi.out");
vector <int> v[250005],l[250005],pos[250005];
int n,q,a[250005],k,sol[250005],use[250005],lft[250005],ok;

 void DF(int x)
 { int i;
   k=0; k++; a[k]=x;
    lft[1]=-1;

  while(k)
  { x=a[k]; use[x]=1;

   for(i=0;i<l[x].size();i++)
    if (l[x][i]<=k-1) sol[pos[x][i]]=a[k-l[x][i]];
    ok=0;

   for(i=lft[k]+1;i<v[x].size();i++)
     if (!use[v[x][i]])
      { lft[k]=i;
        k++; a[k]=v[x][i];
        lft[k]=-1;
         ok=1;
         break;
      }

    if (!ok) k--;
  }
 }

int main()
{ int i,x,y;
    f>>n>>q;
    for(i=1;i<=n;i++)
     { f>>x;
       v[i].push_back(x);
       v[x].push_back(i);
     }


    for(i=1;i<=q;i++)
     { f>>x>>y;
        l[x].push_back(y);
        pos[x].push_back(i);
     }

   for(i=1;i<=n;i++)
    if (!use[i]) DF(i);

  for(i=1;i<=q;i++)
   g<<sol[i]<<"\n";
    return 0;
}