2177. Find Three Consecutive Integers That Sum to a Given Number

Given an integer num, return three consecutive integers (as a sorted array) that sum to num. If num cannot be expressed as the sum of three consecutive integers, return an empty array.

Example 1:

Input: num = 33
Output: [10,11,12]
Explanation: 33 can be expressed as 10 + 11 + 12 = 33.
10, 11, 12 are 3 consecutive integers, so we return [10, 11, 12].

Example 2:

Input: num = 4
Output: []
Explanation: There is no way to express 4 as the sum of 3 consecutive integers.

Constraints:

• 0 <= num <= 1015

Solutions (Rust)

1. Solution

impl Solution {
    pub fn sum_of_three(num: i64) -> Vec<i64> {
        if num % 3 == 0 {
            vec![num / 3 - 1, num / 3, num / 3 + 1]
        } else {
            vec![]
        }
    }
}