Cod sursa(job #971485)

Utilizator andrettiAndretti Naiden andretti Data 9 iulie 2013 13:46:16
Problema Stramosi Scor 90
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.3 kb
#include<stdio.h>
#include<vector>
#define mp make_pair
#define pb push_back
#define popb pop_back
#define maxn 250005
#define maxm 300005
using namespace std;

int n,m,u;
int v[maxn],r[maxn],sol[maxm];
int stack[maxn];
vector <int> l[maxn];
vector < pair<int,int> > t[maxn];

void read()
{
    int i;
    int node,father;
    int x;
    scanf("%d%d",&n,&m);
    for(i=1;i<=n;i++)
    {
        scanf("%d",&x);
        if(x!=0)
        {
            l[x].pb(i);
            l[i].pb(x);
        }
        else r[i]=1;
    }
    for(i=1;i<=m;i++) { scanf("%d%d",&node,&father); t[node].pb(mp(father,i)); }
}

void dfs(int k)
{
    v[k]=1; stack[++u]=k;

    for(unsigned int i=0;i<t[k].size();i++)
    {
        if(u-t[k][i].first>0) sol[t[k][i].second]=stack[u-t[k][i].first];
        else sol[t[k][i].second]=0;
    }

    for(unsigned int i=0;i<l[k].size();i++)
     if(v[l[k][i]]==0)
      dfs(l[k][i]);
    u--;
}

void solve()
{
    int i;
    for(i=1;i<=n;i++)
     if(r[i]) { u=0; dfs(i); }
}

void print()
{
    for(int i=1;i<=m;i++) printf("%d\n",sol[i]);
}

int main()
{
    freopen("stramosi.in","r",stdin);
    freopen("stramosi.out","w",stdout);

    read();
    solve();
    print();

    fclose(stdin);
    fclose(stdout);
    return 0;
}