Define P(x) as the product of primes p with odd exponents in x's factorization. Examples: For x = 18, factorization 21 × 32, P(18) = 2; for x = 45, factorization 32 × 51, P(45) = 5; for x = 50, factorization 21 × 52, P(50) = 2; for x = 210, factorization 21 × 31 × 51 × 71, P(210) = 210.
提示 2
If P(i) = P(j), nums[i] and nums[j] can be grouped together.
