Cod sursa(job #1979674)

Utilizator RaresEGaySopterean Adrian RaresEGay Data 11 mai 2017 08:06:13
Problema Stramosi Scor 50
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.97 kb
#include <fstream>
#include <vector>
#include <stack>

#define MAXN 250001

using namespace std;

ifstream f ("stramosi.in");
ofstream g ("stramosi.out");

stack < int > root;
vector < int > v[MAXN];
vector < int > sol[MAXN];
vector < int > stiva;


int n, m;

void DFS(int u){
    stiva.push_back(u);
    for(int i = 0; i < v[u].size(); ++i){
        for(int j = stiva.size() - 1; j >= 0; --j){
            sol[v[u][i]].push_back(stiva[j]);
        }
        DFS(v[u][i]);
    }
    stiva.erase(stiva.begin() + stiva.size() - 1);
}

int main(){
    f >> n >> m;
    for(int i = 1; i <= n; ++i){
        int x;
        f >> x;
        if(x) v[x].push_back(i);
        else root.push(i);
    }

    while(!root.empty()){
        DFS(root.top());
        root.pop();
    }

    for(int i = 1; i <= m; ++i){
        int x, y;
        f >> x >> y;
        if(y < sol[x].size() + 1) g << sol[x][y - 1] << '\n';
        else g << 0 << '\n';
    }
}