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```
```/// Computing the Levenshtein distance between strings.
///
/// # Examples
///
/// ```
/// let cat = "I Am a Cat";
/// let dog = "I Am a Dog";
///
/// assert_eq!(3, levenshtein::compute(cat, dog));
/// ```
pub fn compute(a: &str, b: &str) -> usize {
let acnt = a.chars().count();
let bcnt = b.chars().count();
let mut _next: usize;
let mut _prev: usize;
let mut c = (0..=acnt).collect::<Vec<usize>>();
for x in 1..=bcnt {
c[0] = x;
_next = x - 1;
for y in 1..=acnt {
_prev = c[y];
let cost = if a.chars().nth(y - 1) != b.chars().nth(x - 1) {
1
} else {
0
};
c[y] = min(c[y] + 1, c[y - 1] + 1, _next + cost);
_next = _prev
}
}
return c[acnt];
}

fn min(a: usize, b: usize, c: usize) -> usize {
if a < b {
if a < c {
return a;
}
} else {
if b < c {
return b;
}
}
return c;
}

#[cfg(test)]
mod tests {
use super::compute;

#[test]
fn it_compute() {
let cat = "I Am a Cat";
let dog = "I Am a Dog";
assert_eq!(3, compute(cat, dog));
}
}
```