Cod sursa(job #1697088)

Utilizator llalexandruLungu Alexandru Ioan llalexandru Data 30 aprilie 2016 18:36:40
Problema Stramosi Scor 80
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.08 kb
#include <fstream>
#include <vector>
#define NM 250005

using namespace std;

ifstream fin("stramosi.in");
ofstream fout("stramosi.out");

vector <int> G[NM];

int M[NM][20], n, m;
bool Valid[NM];

void DFS(int x, int lv, int pre)
{
    int i, c=1;
    M[x][0]=pre;
    for (i=2; i<=lv; i*=2)
    {
        M[x][c]=M[M[x][c-1]][c-1];
        c++;
    }
    int sz=G[x].size();
    for (i=0; i<sz; i++)
    {
        int p=G[x][i];
        if (Valid[p]==0)
        {
            Valid[p]=1;
            DFS(p, lv+1, x);
        }
    }
}

int main()
{
    int i, x, j, c, y;
    fin>>n>>m;
    for (i=1; i<=n; i++)
    {
        fin>>x;

        G[x].push_back(i);
        G[i].push_back(x);
    }
    Valid[0]=1;
    DFS(0, 0, 0);
    for (i=1; i<=m; i++)
    {
        fin>>x>>y;
        c=0;
        while (y>0)
        {
            if (y%2==1)
            {
                x=M[x][c];
            }
            if (x==0)
                break;
            c++;
            y=y/2;
        }
        fout<<x<<'\n';
    }
    return 0;
}