levenshtein distance

1def levenshtein(a, b):
2    m = [[*range(len(a) + 1)] for _ in range(len(b) + 1)]
3    for i in range(len(b) + 1):
4        m[i][0] = i
5    for i in range(1, len(b) + 1):
6        for j in range(1, len(a) + 1):
7            m[i][j] = min(m[i-1][j] + 1, m[i][j-1] + 1, m[i-1][j-1] + (b[i-1] != a[j-1]))
8    return m[-1][-1]

1package main
2
3import "fmt"
4
5// levenshtein distance in Golang
6func levenshtein(str1, str2 []rune) int {
7	s1len := len(str1)
8	s2len := len(str2)
9	column := make([]int, len(str1)+1)
10	for y := 1; y <= s1len; y++ {
11		column[y] = y
12	}
13	for x := 1; x <= s2len; x++ {
14		column[0] = x
15		currkey := x - 1
16		for y := 1; y <= s1len; y++ {
17			oldkey := column[y]
18			incr := 0
19			if str1[y-1] != str2[x-1] {
20				incr = 1
21			}
22			column[y] = min3(column[y]+1, column[y-1]+1, currkey+incr)
23			currkey = oldkey
24		}
25	}
26	return column[s1len]
27}
28
29func min3(a, b, c int) int {
30	if a < b {
31		if a < c { return a }
32	} else {
33		if b < c { return b }
34	}
35	return c
36}
37
38func main(){
39	var str1, str2 = []rune("Monday"), []rune("Friday")
40	fmt.Printf("Distance between Monday and Friday = %d\n", levenshtein(str1, str2))  // 3
41}

1fn levenshtein(word1: &str, word2: &str) -> usize {
2    let s = word1.chars().collect::<Vec<_>>();
3    let t = word2.chars().collect::<Vec<_>>();
4    let slength = s.len() + 1;
5    let tlength = t.len() + 1;
6    let mut m = vec![vec![0]];
7    for i in 1..slength { m[0].push(i); }
8    for j in 1..tlength { m.push(vec![j]); }
9    
10    for j in 1..tlength {
11        for i in 1..slength {
12            let tmp: usize = if s[i-1] == t[j-1] {
13                m[j-1][i-1]
14                } else {
15                1 + std::cmp::min(
16                std::cmp::min(m[j][i-1], m[j-1][i])
17                , m[j-1][i-1])
18            };
19            m[j].push(tmp);
20        }
21    }
22    m[tlength-1][slength-1]
23}
24    
25fn main() {
26    println!("{}", levenshtein("Monday", "Friday"));  // 3
27}

1function levenshtein(s, t) {
2  if(s.length === 0) return t.length; 
3  if(t.length === 0) return s.length;    
4  let m = new Array(s.length + 1).fill(0).map(
5    (_, i) => new Array(t.length + 1).fill(0).map(
6      (_,j) => i*j ? 0 : i+j
7    )
8  )
9  for(let i = 1; i <= s.length; i++) {
10    for(let j = 1; j <= t.length; j++) {
11      if(s[i - 1] === t[j - 1]) {
12        m[i][j] = m[i-1][j-1]
13      } else {
14        m[i][j] = Math.min(m[i - 1][j - 1], m[i - 1][j], m[i][j - 1]) + 1
15      }
16    }
17  }
18  return m[s.length][t.length]
19} 
20
21console.log("Distance between Monday and Friday = %d\n", levenshtein("Monday", "Friday"));  // 3

1test 5