Friends of appropriate ages:

There are n persons on a social media website. You are given an integer array ages where ages[i] is the age of the i^th person.

A Person x will not send a friend request to a person y (x != y) if any of the following conditions is true:

• age[y] <= 0.5 * age[x] + 7
• age[y] > age[x]
• age[y] > 100 && age[x] < 100

Otherwise, x will send a friend request to y.

Note that if x sends a request to y, y will not necessarily send a request to x. Also, a person will not send a friend request to themself.

Return the total number of friend requests made.

 

Example 1:

Input: ages = [16,16]

Output: 2

Explanation: 2 people friend request each other.

Example 2:

Input: ages = [16,17,18]

Output: 2

Explanation: Friend requests are made 17 -> 16, 18 -> 17.

Example 3:

Input: ages = [20,30,100,110,120]

Output: 3

Explanation: Friend requests are made 110 -> 100, 120 -> 110, 120 -> 100.

 

Constraints:

• n == ages.length
• 1 <= n <= 2 * 10⁴
• 1 <= ages[i] <= 120

class Solution {

    public int numFriendRequests(int[] ages) {

        int[][] requests = new int[ages.length][ages.length];

        for (int i = 0; i < ages.length; i++) {

            for (int j = 0; j < ages.length; j++){

                requests[i][j] = 0;

            }

        }

        int sum = 0;

        for (int i = 0; i < ages.length; i++) {

            for (int j = 0; j < ages.length; j++){

                if (i == j) continue;

                if (ages[j] <= 0.5 * ages[i] + 7) continue;

                if (ages[j] > ages[i]) continue;

                if (ages[j] > 100 && ages[i] < 100) continue;

                requests[i][j] = 1;

                sum += 1;

            }

        }

        return sum;

    }

}