LeetCode 825. Friends Of Appropriate Ages

Problem Statement

impl Solution {
    pub fn num_friend_requests(ages: Vec<i32>) -> i32 {
        let mut map = vec![0; 121];
        for age in ages {
            map[age as usize] += 1;
        }
        let mut ans = 0;
        for a in 1..121 {
            let ca = map[a];
            for b in 1..121 {
                let cb = map[b];
                if b as f64 <= 0.5 * a as f64 + 7 as f64 || b > a || b > 100 && a < 100 {
                    continue;
                }
                ans += ca * cb;
                if a == b {
                    ans -= ca;
                }
            }
        }
        return ans;
    }
}