42 lines
993 B
Go
42 lines
993 B
Go
package main
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type shuffleDirection int
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const (
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left shuffleDirection = iota
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right
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)
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// shuffle creates a new list where an element in one position is repositioned
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// to the index of another element. All affected elements then shuffle one place to the left
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// or right depending on the direction of the move.
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func shuffle(list []any, oldPos, newPos int) []any {
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var direction shuffleDirection
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if newPos < oldPos {
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direction = right
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} else {
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direction = left
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}
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newList := make([]any, len(list))
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for i := range list {
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switch {
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case (direction == right) && (i < newPos || i > oldPos):
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newList[i] = list[i]
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case (direction == right) && (i == oldPos):
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newList[newPos] = list[i]
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case (direction == right):
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newList[i+1] = list[i]
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case (direction == left) && (i < oldPos || i > newPos):
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newList[i] = list[i]
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case (direction == left) && (i == oldPos):
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newList[newPos] = list[i]
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case (direction == left):
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newList[i-1] = list[i]
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}
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}
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return newList
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}
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