Count factors of given number n.
A positive integer D is a factor of a positive integer N if there exists an integer M such that N = D * M.
For example, 6 is a factor of 24, because M = 4 satisfies the above condition (24 = 6 * 4).
Write a function:
func Solution(N int) int
that, given a positive integer N, returns the number of its factors.
For example, given N = 24, the function should return 8, because 24 has 8 factors, namely 1, 2, 3, 4, 6, 8, 12, 24. There are no other factors of 24.
Write an efficient algorithm for the following assumptions:
N is an integer within the range [1..2,147,483,647].
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找出該數的因子個數
尋遍該數字平方根的整數, 每次可以獲得2個因子
https://app.codility.com/programmers/lessons/10-prime_and_composite_numbers/count_factors/
package CountFactors
import (
"math"
)
func Solution(N int) int {
result := 0
for i := 1; i <= int(math.Pow(float64(N), 0.5)); i++ {
if N%i == 0 {
if i*i == N {
// fmt.Println("+1 : ", i)
result++
} else {
// fmt.Println("+2 : ", i)
result += 2
}
}
}
return result
}