Cod sursa(job #2720165)

Utilizator mihnea03Ciocioiu Mihnea mihnea03 Data 10 martie 2021 17:19:40
Problema Stramosi Scor 70
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1 kb
#include <fstream>
#include <vector>
#define dim 250010
using namespace std;
vector<int> a[dim];
int niv[dim];
int t[dim];
int f[dim];
int i,n,m,q,p,nod;

void dfs (int nod, int nivel) {
    niv[nod]=nivel;
    f[nod]=1;
    for (auto vecin:a[nod]) {
        if (f[vecin]==0)
            dfs(vecin,nivel+1);
    }
}

int main() {
    ifstream fin("stramosi.in");
    ofstream fout("stramosi.out");
    fin>>n>>q;
    for (i=1;i<=n;i++) {
        fin>>t[i];
        if (t[i]==0) continue;
        a[i].push_back(t[i]);
        a[t[i]].push_back(i);
    }
    for (i=1;i<=n;i++) {
        if (t[i]==0) {
            dfs(i,1);
        }
    }
    for (;q--;) {
        fin>>nod>>p;///care este al p-lea stramos al lui nod
        p=niv[nod]-p;
        if (p<=0) {
            fout<<0<<"\n";
            continue;
        }
        else {
            while (niv[nod]!=p&&nod) {
                nod=t[nod];
            }
            fout<<nod<<"\n";
        }
    }
    return 0;
}