Perfect number

Math

48.0% acceptance

Feb 19, 2026

1286

1285

A perfect number is a positive integer that is equal to the sum of its positive divisors, excluding the number itself. A divisor of an integer x is an integer that can divide x evenly. Given an integer n, return true if n is a perfect number, otherwise return false.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn check_perfect_number(num: i32) -> bool {
    if num <= 1 {
      return false;
    }
    let mut sum = 1i32;
    let mut i = 2i32;
    while i * i <= num {
      if num % i == 0 {
        sum += i;
        if i != num / i {
          sum += num / i;
        }
      }
      i += 1;
    }
    sum == num
  }
}