pub fn levenshtein(a: &str, b: &str) -> usize {
let length_a = a.chars().count();
let length_b = b.chars().count();
let mut result = 0;
if a == b {
return result;
}
if length_a == 0 {
return length_b;
}
if length_b == 0 {
return length_a;
}
let mut cache: Vec<usize> = vec![0; length_a];
let mut index_a = 0;
let mut distance_a;
let mut distance_b;
while index_a < length_a {
index_a += 1;
cache[index_a - 1] = index_a;
}
for (index_b, code_b) in b.chars().enumerate() {
result = index_b;
distance_a = index_b;
for (index_a, code_a) in a.chars().enumerate() {
distance_b = if code_a == code_b {
distance_a
} else {
distance_a + 1
};
distance_a = cache[index_a];
result = if distance_a > result {
if distance_b > result {
result + 1
} else {
distance_b
}
} else {
if distance_b > distance_a {
distance_a + 1
} else {
distance_b
}
};
cache[index_a] = result;
}
}
result
}