Task · algorithms easy Python ·

Count primes

def count_primes(n: int) -> int:

count_primes(10)  # -> 4
count_primes(0)  # -> 0
count_primes(2)  # -> 0

• #1Anthropic Claude Haiku 5.5solved · 10 of 10 testsanswer in 1.1 s · runtime 96 ms · $0.0001

  ✓	count_primes(10)expected 4	<1 ms
  ✓	count_primes(0)expected 0	<1 ms
  ✓	count_primes(2)expected 0	<1 ms

  ✓ <1 ms✓ <1 ms✓ <1 ms✓ <1 ms✓ <1 ms✓ <1 ms⏱ 90 ms
  Code

  def count_primes(n: int) -> int:
      if n <= 2:
          return 0
      size = n
      sieve = bytearray([1]) * size
      sieve[0] = 0
      sieve[1] = 0
      i = 2
      while i * i < size:
          if sieve[i]:
              start = i * i
              count = (size - 1 - start) // i + 1
              sieve[start::i] = bytes(count)
          i += 1
      return sum(sieve)

• #2SpaceXAI Grok Build 0.1solved · 10 of 10 testsanswer in 6.9 s · runtime 622 ms · $0.0021

  ✓	count_primes(10)expected 4	<1 ms
  ✓	count_primes(0)expected 0	<1 ms
  ✓	count_primes(2)expected 0	<1 ms

  ✓ <1 ms✓ <1 ms✓ <1 ms✓ <1 ms✓ 1 ms✓ 1 ms⏱ 615 ms
  Code

  def count_primes(n: int) -> int:
      if n <= 2:
          return 0
      is_prime = [True] * n
      is_prime[0] = is_prime[1] = False
      for i in range(2, int(n**0.5) + 1):
          if is_prime[i]:
              for j in range(i*i, n, i):
                  is_prime[j] = False
      return sum(is_prime)

• #2DeepSeek V4 Pro 0423solved · 10 of 10 testsanswer in 2.1 s · runtime 628 ms · $0.0004

  ✓	count_primes(10)expected 4	<1 ms
  ✓	count_primes(0)expected 0	<1 ms
  ✓	count_primes(2)expected 0	1 ms

  ✓ <1 ms✓ <1 ms✓ 2 ms✓ <1 ms✓ 2 ms✓ 2 ms⏱ 618 ms
  Code

  def count_primes(n: int) -> int:
      if n <= 2:
          return 0
      
      # Sieve of Eratosthenes
      is_prime = [True] * n
      is_prime[0] = is_prime[1] = False
      
      for i in range(2, int(n ** 0.5) + 1):
          if is_prime[i]:
              for j in range(i * i, n, i):
                  is_prime[j] = False
      
      return sum(is_prime)

• #4MoonshotAI Kimi K2.7 Codenot solved · 0 of 10 testsanswer in 96 s · $0.01

  the answer was cut off before the code ended

  ✗	count_primes(10)expected 4no code in the answer	—
  ✗	count_primes(0)expected 0no code in the answer	—
  ✗	count_primes(2)expected 0no code in the answer	—

  ✗ no code in the answer✗ no code in the answer✗ no code in the answer✗ no code in the answer✗ no code in the answer✗ no code in the answer⏱ no code in the answer

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