Submission #1240197

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Source Code Expand

import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    long a = sc.nextLong();
    String k = sc.next();
    long[] b = new long[(int)N];
    for(int i = 0; i < N; i++) {
      b[i] = sc.nextLong();
    }
    ArrayList<Long> list = new ArrayList<Long>();
    list.add(a);
    long[] f = new long[(int)N];
    f[0] = a;
    long presence = a;
    long s = 0;
    long g = 1;
    for(int i = 0; i < N; i++) {
      presence = b[(int)presence - 1];
      f[i + 1] = presence;
      if(list.contains(presence)) {
        for(int j = 0; j < N; j++) {
          if(f[j] == presence) {
            s = (long)j;
            g = (long)(i + 1) - s;
            break;
          }
        }
        break;
      } else {
        list.add(presence);
      }
    }
    long ans = 0;
    // s+tをgで割った余り
    long r = func(k, g);
    while(r < s) {
      r += g;
    }
    ans = f[(int)r];
    System.out.println(ans);
  }

  public static long func(String k, long g) {
    if(k.length() <= 18) return (Long.parseLong(k)) % g;
    String sub = k.substring(0, k.length() - 1);
    long d = Long.parseLong(String.valueOf(k.charAt(k.length() - 1)));
    long a = (func(sub, g) * 10 + d) % g;
    return a; 
  }
}

Submission Info

Judge Result