Randomization (무작위화)

import random
​
def fisher_yates(arr):
  """In-place Fisher-Yates shuffle, O(N)"""
  for i in range(len(arr) - 1, 0, -1):
      j = random.randint(0, i)
      arr[i], arr[j] = arr[j], arr[i]
​
def monte_carlo_pi(trials: int) -> float:
  inside = 0
  for _ in range(trials):
      x = random.random()
      y = random.random()
      if x * x + y * y <= 1.0:
          inside += 1
  return 4.0 * inside / trials
​
def miller_rabin(n: int, k: int = 10) -> bool:
  """Monte Carlo primality test, error 4^(-k)"""
  if n < 2: return False
  if n in (2, 3): return True
  if n % 2 == 0: return False
​
  s, d = 0, n - 1
  while d % 2 == 0:
      s += 1; d //= 2
​
  for _ in range(k):
      a = random.randrange(2, n - 1)
      x = pow(a, d, n)
      if x == 1 or x == n - 1:
          continue
      for _ in range(s - 1):
          x = pow(x, 2, n)
          if x == n - 1:
              break
      else:
          return False
  return True
​
mode = int(input())
if mode == 0:
  n = int(input())
  a = list(range(1, n + 1))
  random.seed(42)
  fisher_yates(a)
  print(" ".join(map(str, a)))
else:
  trials = int(input())
  random.seed(42)
  print(f"{monte_carlo_pi(trials):.6f}")

import java.util.*;
import java.io.*;
​
public class Main {
  static int rngState = 42;
  static int lcgRand(int n) {
      rngState = (rngState * 1103515245 + 12345) & 0x7fffffff;
      return rngState % n;
  }
​
  public static void main(String[] args) throws IOException {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      int mode = Integer.parseInt(br.readLine());
​
      if (mode == 0) {
          int n = Integer.parseInt(br.readLine());
          int[] a = new int[n];
          for (int i = 0; i < n; i++) a[i] = i + 1;
          for (int i = n - 1; i > 0; i--) {
              int j = lcgRand(i + 1);
              int t = a[i]; a[i] = a[j]; a[j] = t;
          }
          StringBuilder sb = new StringBuilder();
          for (int x : a) sb.append(x).append(" ");
          System.out.println(sb);
      } else {
          int trials = Integer.parseInt(br.readLine());
          int inside = 0;
          for (int i = 0; i < trials; i++) {
              int x = lcgRand(1000001);
              int y = lcgRand(1000001);
              if ((long)x * x + (long)y * y
                  <= (long)1000000 * 1000000)
                  inside++;
          }
          double pi = 4.0 * inside / trials;
          System.out.printf("%.6f%n", pi);
      }
  }
}