package levenshtein import ( "math" "strings" ) // DamerauLevenshteinDistance calculates the damerau-levenshtein distance between s1 and s2. // Reference: [Damerau-Levenshtein Distance](http://en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance) // Note that this calculation's result isn't normalized. (not between 0 and 1.) // and if s1 and s2 are exactly the same, the result is 0. func DamerauLevenshteinDistance(s1, s2 string) int { if s1 == s2 { return 0 } s1Array := strings.Split(s1, "") s2Array := strings.Split(s2, "") lenS1Array := len(s1Array) lenS2Array := len(s2Array) m := make([][]int, lenS1Array+1) var cost int for i := range m { m[i] = make([]int, lenS2Array+1) } for i := 0; i < lenS1Array+1; i++ { for j := 0; j < lenS2Array+1; j++ { if i == 0 { m[i][j] = j } else if j == 0 { m[i][j] = i } else { cost = 0 if s1Array[i-1] != s2Array[j-1] { cost = 1 } m[i][j] = min(m[i-1][j]+1, m[i][j-1]+1, m[i-1][j-1]+cost) if i > 1 && j > 1 && s1Array[i-1] == s2Array[j-2] && s1Array[i-2] == s2Array[j-1] { m[i][j] = min(m[i][j], m[i-2][j-2]+cost) } } } } return m[lenS1Array][lenS2Array] } // min returns the minimum number of passed int slices. func min(is ...int) int { min := math.MaxInt32 for _, v := range is { if min > v { min = v } } return min }