Cod sursa(job #974412)

Utilizator crisbodnarCristian Bodnar crisbodnar Data 17 iulie 2013 10:20:30
Problema Stramosi Scor 90
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.09 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

#define u unsigned int
#define f first
#define s second

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

const int N = 350010;
const int M = 450010;

int n, m, top, st[M];
typedef pair <int, int> query;
vector <int> a[N], sol(M, 0), vfst;
vector <query> q[N];

void dfs(int x)
{
    st[++top] = x;
    for(u i=0; i<q[x].size(); i++)
    {
        int nrq = q[x][i].f, str = q[x][i].s;
        if(top > str) sol[nrq] = st[top - str];
            else sol[nrq] = 0;
    }

    for(u i=0; i<a[x].size(); i++)
        dfs(a[x][i]);
    --top;
}

int main()
{
    fin>>n>>m;
    int x, y;

    for(int i=1; i<=n; i++)
    {
        fin>>x;
        if(x) a[x].push_back(i);
        else vfst.push_back(i);
    }

    for(int i=1; i<=m; i++)
    {
        fin>>x>>y;
        q[x].push_back(query(i, y));
    }

    for(u i = 0; i < vfst.size(); i++)
        dfs(vfst[i]);
    for(int i=1; i<=m; i++)
        fout<<sol[i]<<'\n';
    return 0;
}