pe23 in Go

pe23.go

package main

const n1, n2 int = 1, 28123
func main() {
    // All abundant 'n's from n1 to n2.
    abundant := make([]int, 0)
    for n := n1; n <= n2; n++ {
        if n < sumDivisors(n) {
            abundant = append(abundant, n)
        }
    }
    // A map where keys of abundant sums are set to true.
    sp  := sumsPairs(abundant)
    // Sum of the 'i's that aren't true in the map.
    sum := 0
    for i := n1; i < n2; i++ {
        if sp[i] == false {
            sum += i
        }
    }
    println(sum)
}

func sumsPairs(xs []int) map[int]bool {
    r := make(map[int]bool)
    for i := len(xs)-1; i > 0; i-- {
        for j := i-1; j >= 0; j-- {
            r[xs[i] + xs[j]] = true
        }
    }
    return r
}

func sumDivisors(n int) int {
    s := 1
    for i := n/2; i > 1; i-- {
        if n % i == 0 {
            s += i
        }
    }
    return s
}