raindrops.go

package raindrops

import (
    "bytes"
    "fmt"
)

func Convert(v int) string {
    fs := findRelevantFactorsFor(v)
    return formatFactorsOf(v, fs)
}

func findRelevantFactorsFor(v int) (factors []int) {
    for _, factor := range []int{3, 5, 7} {
        if v % factor == 0 {
            factors = append(factors, factor)
        }
    }
    return
}

var dictFactorToStr = map[int]string{
    3: "Pling",
    5: "Plang",
    7: "Plong",
}

func formatFactorsOf(v int, factors []int) string {
    if len(factors) == 0 {
        return fmt.Sprintf("%d", v) 
    } else {
        var buf bytes.Buffer
        for _, factor := range factors {
            buf.WriteString(dictFactorToStr[factor])
        }
        return buf.String()
    }
}