829. 连续整数求和-leetcode

题目：给定一个正整数 N，试求有多少组连续正整数满足所有数字之和为 N?

示例 1:

输入: 5
输出: 2

解释: 5 = 5 = 2 + 3，共有两组连续整数([5],[2,3])求和后为 5。

示例 2:

输入: 9
输出: 3

解释: 9 = 9 = 4 + 5 = 2 + 3 + 4
示例 3:

输入: 15
输出: 4

解释: 15 = 15 = 8 + 7 = 4 + 5 + 6 = 1 + 2 + 3 + 4 + 5

说明: 1 <= N <= 10 ^ 9

/* 
N = (p+0)+(p+1)+(p+2)+...+(p+i-1)

  = p*i +i*(i-1)/2
  
  ===>
        2*N = (p*2+i-1)*i (p,i都是正整数)
 */ 

import "math"
func consecutiveNumbersSum(N int) int {
	var sum = 0
	dataChan := make(chan int, 10)
	outChan := make(chan byte, 10)

go func() {
	defer close(dataChan)
	for i := 1; float64(i) <= math.Sqrt(float64(2*N)); i++ {
		if (2*N)%i == 0 {
			dataChan <- i
		}
	}
}()

go func() {
	for {
		if i, ok := <-dataChan; !ok {
			close(outChan)
			return
		} else {
			p := (2*N)/i - i - 1
			if p >= 0 && (p&1 == 0) {
				// fmt.Println("offset,i", p/2, i)
				outChan <- 0
			}
		}
	}

}()

for {
	if _, ok := <-outChan; ok {
		sum++
	} else {
		break
	}
}
return sum
}