Function floor_sqrt 

pub fn floor_sqrt(n: u64) -> u64

floor(sqrt(n)) を返す。

Examples

use floor_sqrt::floor_sqrt;

assert_eq!(floor_sqrt(0), 0);
assert_eq!(floor_sqrt(1), 1);
assert_eq!(floor_sqrt(2), 1);
assert_eq!(floor_sqrt(3), 1);
assert_eq!(floor_sqrt(4), 2);
assert_eq!(floor_sqrt(5), 2);