59 lines
955 B
Go
59 lines
955 B
Go
package aoc
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import (
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"bufio"
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"fmt"
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"os"
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)
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func Runner[R any, F func(*bufio.Scanner) (R, error)](run F) (R, error) {
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if len(os.Args) != 2 {
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fmt.Fprintln(os.Stderr, "Usage:", os.Args[0] , "FILE")
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}
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input, err := os.Open(os.Args[1])
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if err != nil {
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fmt.Fprintln(os.Stderr, err)
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}
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scan := bufio.NewScanner(input)
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return run(scan)
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}
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func Reverse[T any](arr []T) []T {
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for i := 0; i < len(arr)/2; i++ {
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arr[i], arr[len(arr)-i-1] = arr[len(arr)-i-1], arr[i]
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}
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return arr
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}
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// greatest common divisor (GCD) via Euclidean algorithm
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func GCD(a, b uint64) uint64 {
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for b != 0 {
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t := b
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b = a % b
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a = t
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}
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return a
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}
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// find Least Common Multiple (LCM) via GCD
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func LCM(integers ...uint64) uint64 {
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if len(integers) == 0 {
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return 0
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}
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if len(integers) == 1 {
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return integers[0]
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}
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a, b := integers[0], integers[1]
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result := a * b / GCD(a, b)
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for _, c := range integers[2:] {
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result = LCM(result, c)
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}
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return result
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}
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