#![allow(dead_code)]
pub fn levenshtein_distance(a: &str, b: &str) -> usize {
let a_chars: Vec<char> = a.chars().collect();
let b_chars: Vec<char> = b.chars().collect();
let a_len = a_chars.len();
let b_len = b_chars.len();
if a_len == 0 {
return b_len;
}
if b_len == 0 {
return a_len;
}
let mut matrix = vec![vec![0; b_len + 1]; a_len + 1];
for i in 0..=a_len {
matrix[i][0] = i;
}
for j in 0..=b_len {
matrix[0][j] = j;
}
for i in 1..=a_len {
for j in 1..=b_len {
let cost = if a_chars[i - 1] == b_chars[j - 1] {
0
} else {
1
};
matrix[i][j] = (matrix[i - 1][j] + 1)
.min(matrix[i][j - 1] + 1)
.min(matrix[i - 1][j - 1] + cost);
}
}
matrix[a_len][b_len]
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_distance() {
assert_eq!(levenshtein_distance("kitten", "sitting"), 3);
}
}