Cod sursa(job #2022933)

Utilizator Dan_RadulescuRadulescu Dan Dan_Radulescu Data 17 septembrie 2017 19:15:56
Problema Stramosi Scor 0
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.46 kb
#include <bits/stdc++.h>
#define N 250001
#define M 300001
using namespace std;

FILE *f1 = fopen("stramosi.in", "r");
FILE *f2 = fopen("stramosi.out", "w");

int st[N], nr, n, m, i, a, p, q, father[N], v[18][N], vis[N], power, index, res;
vector<int> G[N];

void DFS(int k)
{
    vis[k] = 1;
    nr++;
    st[nr] = k;
    int i;
    for (i = 0; i < G[k].size(); i++)
        if (vis[G[k][i]] == 0)
            DFS(G[k][i]);

    nr--;
    int power = 1, index = 1;
    while(power <= nr)
    {
        v[index][k] = st[nr - power + 1];
        power = power * 2;
        index++;
    }
}

int main()
{
    fscanf(f1, "%d%d", &n, &m);
    for (i = 1; i <= n; i++)
    {
        fscanf(f1, "%d", &father[i]);
        if (father[i] != 0)
            G[father[i]].push_back(i);
    }
    for (i = 1; i <= n; i++)
        if (father[i] == 0)
        {
            DFS(i);
            nr = 0;
        }

    for (i = 1; i <= m; i++)
    {
        fscanf(f1, "%d%d", &q, &p);
        power = 1; index = 1;
        while(power <= p)
        {
            index++;
            power = power * 2;
        }
        index--;
        power = power / 2;
        index = v[index][q];
        res = index;
        while (index != 0 && power <= p)
        {
            power++;
            res = index;
            index = father[index];
        }
        fprintf(f2, "%d\n", res);
    }
    fclose(f1);
    fclose(f2);
    return 0;
}