edit-distance/werner.go

package editdistance

import (
	"strings"
)

func Werner(a, b string) int {

	phrase_a := strings.Fields(a)
	phrase_b := strings.Fields(b)

	m := len(phrase_a) + 1
	n := len(phrase_b) + 1
	distances := make([][]int, n)
	for i := range distances {
		distances[i] = make([]int, m)
	}
	// make the inital numbers on the top
	for i := 1; i < n; i++ {
		distances[i][0] = i
	}
	// make the inital numbers on the left side
	for i := 1; i < m; i++ {
		distances[0][i] = i
	}

	for i := 1; i < n; i++ {
		for j := 1; j < m; j++ {
			subCost := 0
			if strings.EqualFold(phrase_a[j-1], phrase_b[i-1]) {
				subCost = 0
			} else {
				subCost = 1
			}
			value := min(
				distances[i-1][j]+1,
				distances[i][j-1]+1,
				distances[i-1][j-1]+subCost,
			)
			distances[i][j] = value
		}
	}

	return distances[n-1][m-1]
}