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58 lines
1.2 KiB
Go
58 lines
1.2 KiB
Go
7 years ago
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package levenshtein
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// Distance Levenshtein distance
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// The Levenshtein distance between two strings is defined as the minimum
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// number of edits needed to transform one string into the other, with the
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// allowable edit operations being insertion, deletion, or substitution of
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// a single character
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// http://en.wikipedia.org/wiki/Levenshtein_distance
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//
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// This implemention is optimized to use O(min(m,n)) space.
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// It is based on the optimized C version found here:
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// http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Levenshtein_distance#C
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func Distance(str1, str2 string) int {
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var cost, lastdiag, olddiag int
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s1 := []rune(str1)
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s2 := []rune(str2)
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lenS1 := len(s1)
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lenS2 := len(s2)
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column := make([]int, lenS1+1)
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for y := 1; y <= lenS1; y++ {
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column[y] = y
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}
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for x := 1; x <= lenS2; x++ {
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column[0] = x
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lastdiag = x - 1
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for y := 1; y <= lenS1; y++ {
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olddiag = column[y]
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cost = 0
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if s1[y-1] != s2[x-1] {
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cost = 1
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}
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column[y] = min(
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column[y]+1,
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column[y-1]+1,
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lastdiag+cost)
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lastdiag = olddiag
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}
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}
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return column[lenS1]
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}
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func min(a, b, c int) int {
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if a < b {
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if a < c {
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return a
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}
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} else {
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if b < c {
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return b
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}
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}
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return c
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}
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