72 lines
1.7 KiB
Go
72 lines
1.7 KiB
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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// shuffleFuncOne 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 shuffleFuncOne one place to the left
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// or right depending on the direction of the move.
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func shuffleFuncOne(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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// shuffleFuncTwo produces the same output as shuffleFuncOne using a slightly different method.
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// The original slice is copied into a new slice and the element is immediately placed in the new
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// position. The for loop then only focuses on the elements in range between the two positions and
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// are shuffled left or right as required.
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func shuffleFuncTwo(list []any, oldPos, newPos int) []any {
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newList := make([]any, len(list))
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copy(newList, list)
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newList[newPos] = list[oldPos]
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if newPos < oldPos {
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for i := newPos; i <= oldPos; i++ {
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if i != oldPos {
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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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for i := oldPos; i <= newPos; i++ {
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if i != oldPos {
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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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