README.md

970. Powerful Integers

Given two positive integers x and y, an integer is powerful if it is equal to x^i + y^j for some integers i >= 0 and j >= 0.

Return a list of all powerful integers that have value less than or equal to bound.

You may return the answer in any order. In your answer, each value should occur at most once.

Example 1:

Input: x = 2, y = 3, bound = 10
Output: [2,3,4,5,7,9,10]
Explanation:
2 = 2^0 + 3^0
3 = 2^1 + 3^0
4 = 2^0 + 3^1
5 = 2^1 + 3^1
7 = 2^2 + 3^1
9 = 2^3 + 3^0
10 = 2^0 + 3^2

Example 2:

Input: x = 3, y = 5, bound = 15
Output: [2,4,6,8,10,14]

Note:

• 1 <= x <= 100
• 1 <= y <= 100
• 0 <= bound <= 10^6

Solutions (Rust)

1. Brute Force

use std::collections::HashSet;

impl Solution {
    pub fn powerful_integers(x: i32, y: i32, bound: i32) -> Vec<i32> {
        let mut set = HashSet::new();

        for i in 0..20 {
            for j in 0..20 {
                let pow_int = x.saturating_pow(i).saturating_add(y.saturating_pow(j));

                if pow_int <= bound {
                    set.insert(pow_int);
                }
            }
        }

        set.drain().collect()
    }
}