28 lines
682 B
Go
28 lines
682 B
Go
package tree
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func commonSnapshotForTwoPaths(ourPath []string, theirPath []string) (string, error) {
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var i int
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var j int
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OuterLoop:
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// find starting point from the right
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for i = len(ourPath) - 1; i >= 0; i-- {
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for j = len(theirPath) - 1; j >= 0; j-- {
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// most likely there would be only one comparison, because mostly the snapshot path will start from the root for nodes
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if ourPath[i] == theirPath[j] {
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break OuterLoop
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}
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}
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}
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if i < 0 || j < 0 {
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return "", ErrNoCommonSnapshot
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}
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// find last common element of the sequence moving from right to left
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for i >= 0 && j >= 0 {
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if ourPath[i] == theirPath[j] {
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i--
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j--
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}
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}
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return ourPath[i+1], nil
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}
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