Validate a siteswap pattern

siteswap_validator.go

package main

import (
	"errors"
	"fmt"
)

func isValidSiteswap(pattern []int) error {
	total := 0
	numBeats := 0
	for _, x := range pattern {
		total += x
		if numBeats < x {
			numBeats = x
		}
	}

	if total%len(pattern) != 0 {
		return errors.New(fmt.Sprintf(
			"Pattern average is not a whole number"))
	}

	beats := make([]bool, numBeats)
	for i, x := range pattern {
		if beats[(i+x)%numBeats] {
			return errors.New(fmt.Sprintf(
				"Conflict on beat %d", i+x))
		} else {
			beats[(i+x)%numBeats] = true
		}
	}

	return nil
}

func main() {
	isValidSiteswap([]int{5})
	// nil

	isValidSiteswap([]int{5, 3, 1})
	// nil

	isValidSiteswap([]int{4, 4, 1})
	// nil

	isValidSiteswap([]int{4, 4, 4, 1})
	// Pattern average is not a whole number

	isValidSiteswap([]int{5, 1, 3})
	// Conflict on beat 5
}