// Kth Factor of N
// The idea is to check for each number in the range [N, 1], and print the Kth number that divides N completely.
pub fn kth_factor(n: i32, k: i32) -> i32 {
let mut factors: Vec<i32> = Vec::new();
let k = (k as usize) - 1;
for i in 1..=n {
if n % i == 0 {
factors.push(i);
}
if let Some(number) = factors.get(k) {
return *number;
}
}
-1
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_1() {
assert_eq!(kth_factor(12, 3), 3);
}
#[test]
fn test_2() {
assert_eq!(kth_factor(7, 2), 7);
}
#[test]
fn test_3() {
assert_eq!(kth_factor(4, 4), -1);
}
#[test]
fn test_4() {
assert_eq!(kth_factor(950, 5), 19);
}
}