g0801_0900.s0825_friends_of_appropriate_ages

Class Solution

java.lang.Object

g0801_0900.s0825_friends_of_appropriate_ages.Solution

public class Solution
extends Object

825 - Friends Of Appropriate Ages.

Medium

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

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	numFriendRequests(int[] ages)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

numFriendRequests

public int numFriendRequests(int[] ages)