code: func primeFactors(n int64) map[int64]int {
  	factors := make(map[int64]int)
  	for i := int64(2); i <= n; i++ {
  		div, mod := n/i, n%i
  		for mod == 0 {
  			factors[i]++
  			n = div
  			div, mod = n/i, n%i
  		}
  	}
  	return factors
  }
docs: // Returns map of {integerFactor: count, ...}
  // This is a naive algorithm that will not work well for large prime n.