Solution.rs

impl Solution {
    pub fn my_sqrt(x: i32) -> i32 {
        let mut l = 0;
        let mut r = x;

        while l < r {
            let mid = (l + r + 1) / 2;

            if mid > x / mid {
                r = mid - 1;
            } else {
                l = mid;
            }
        }

        l
    }
}