Cod sursa(job #2252787)

Utilizator mouse_wirelessMouse Wireless mouse_wireless Data 3 octombrie 2018 02:30:14
Problema Stramosi Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.66 kb
#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<int, int> pii;
#define CHECK(x) if(!(x)) return false;
#define CHECKRET(x, y) if(!(x)) return (y);
#define SKIP(x) if((x)) continue;

#ifdef INFOARENA
#define ProblemName "stramosi"
#endif

#define MCONCAT(A, B) A B
#ifdef ProblemName
#define InFile MCONCAT(ProblemName, ".in")
#define OuFile MCONCAT(ProblemName, ".out")
#else
#define InFile "fis.in"
#define OuFile "fis.out"
#endif

const int MAXBUF = 30000000;
char parseBuf[MAXBUF];
char *head;
bool isDigit[255];

void parseInit() {
  int a = fread(parseBuf, 1, MAXBUF, stdin);
  parseBuf[a] = 0;
  head = parseBuf;
  memset(isDigit, 0, sizeof isDigit);
  for (int i = '0'; i <= '9'; ++i)
    isDigit[i] = true;
}

int nextInt() {
  int ans = 0;
  for (; !isDigit[*head]; ++head);
  for (; isDigit[*head]; ++head)
    ans = ans * 10 + (*head) - '0';
  return ans;
}


const int MAXN = 250010;
const int MAXLOG = 20;

int p[MAXLOG][MAXN];
int N;

int main() {
  assert(freopen(InFile, "r", stdin));
  assert(freopen(OuFile, "w", stdout));
  parseInit();
  N = nextInt();
  int Q = nextInt();
  memset(p, 0xFF, sizeof p);
  for (int i = 0; i < N; ++i) {
    p[0][i] = nextInt();
    --p[0][i];
  }
  for (int l = 1; l < MAXLOG; ++l)
    for (int i = 0; i < N; ++i) {
      SKIP(p[l - 1][i] < 0);
      p[l][i] = p[l - 1][p[l - 1][i]];
    }
  while (Q--) {
    int x = nextInt(), nr = nextInt();
    --x;
    for (int i = MAXLOG - 1; i >= 0 && x >= 0; --i) {
      int pw = (1 << i);
      SKIP(pw > nr);
      nr -= pw;
      x = p[i][x];
    }
    printf("%d\n", x + 1);
  }
  return 0;
}