46 lines
974 B
Go
46 lines
974 B
Go
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package lsproduct
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import "fmt"
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// TestVersion defines version testing.
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const TestVersion = 1
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// LargestSeriesProduct Takes an input string of digits
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// and a length for the series. It returns the largest
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// series product from that string of that length.
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func LargestSeriesProduct(input string, size int) (int, error) {
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if size == 0 {
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return 1, nil
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} else if size > len(input) {
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return 0, fmt.Errorf("Invalid Span Size")
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}
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var high int
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for i := 0; i < (len(input) - size + 1); i++ {
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try := GetProduct(input[i : i+size])
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if try < 0 {
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return 0, fmt.Errorf("Invalid input")
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}
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if try > high {
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high = try
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}
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}
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return high, nil
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}
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// GetProduct takes a string of numbers, splits it up
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// and returns the product of them
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func GetProduct(input string) int {
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if len(input) > 0 {
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total := 1
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for i := range input {
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next := input[i] - 48
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if next < 0 || next > 9 {
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return -1
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}
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total = total * int(next)
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}
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return total
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}
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return 0
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}
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