Cod sursa(job #1468771)

Utilizator bogdan10bosBogdan Sitaru bogdan10bos Data 6 august 2015 22:25:52
Problema Stramosi Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.13 kb
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <deque>

#define INF ( (1 << 30) - 1 + (1 << 30) )
#define mod 666013

using namespace std;
int n, m, i, j, r, x, y, pt[250005];
int str[23][250005];
int stramos(int st, int ord)
{
    if(ord == 0)
        return st;
    int x = pt[ord];
    return stramos( str[x][st], ord - (1 << x) );
}
int main()
{
    freopen("stramosi.in", "r", stdin);
    freopen("stramosi.out", "w", stdout);

    scanf("%d%d", &n, &m);
    for(i = 1; i <= n; i++)
        scanf("%d", &str[0][i]);

    for(i = 1; i <= 20; i++)
        for(j = 1; j <= n; j++)
            str[i][j] = str[i - 1][ str[i - 1][j] ];

    pt[1] = 0;
    for(i = 1; i <= n; i++)
    {
        pt[i] = pt[i - 1];
        if( (2 << pt[i]) == i )
            pt[i]++;
    }

    while(m--)
    {
        scanf("%d%d", &x, &y);
        if(y > n)
        {
            printf("0\n");
            continue;
        }

        r = stramos(x , y);
        printf("%d\n", r);
    }

    return 0;
}