Easy

Quiz

#507 Perfect Number

APPROACH

A positive integer is called perfect when its value equals the sum of all its proper divisors — that is, all divisors except the number itself. A proper divisor of x is any positive integer less than x that divides x without a remainder.

Given an integer n, return true if n is a perfect number, or false otherwise.

Example 1:

Input: num = 28

Output: true

Explanation: 28 = 1 + 2 + 4 + 7 + 14

1, 2, 4, 7, and 14 are all divisors of 28.

Example 2:

Input: num = 7

Output: false

1 of 4

1:00

What is the optimal approach for this problem?