LeetCode in Kotlin

970. Powerful Integers

Medium

Given three integers x, y, and bound, return a list of all the powerful integers that have a value less than or equal to bound.

An integer is powerful if it can be represented as xi + yj for some integers i >= 0 and j >= 0.

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 = 2⁰ + 3⁰

3 = 2¹ + 3⁰

4 = 2⁰ + 3¹

5 = 2¹ + 3¹

7 = 2² + 3¹

9 = 2³ + 3⁰

10 = 2⁰ + 3²

Example 2:

Input: x = 3, y = 5, bound = 15

Output: [2,4,6,8,10,14]

Constraints:

• 1 <= x, y <= 100
• 0 <= bound <= 106

Solution

import kotlin.math.log10
import kotlin.math.pow

class Solution {
    fun powerfulIntegers(x: Int, y: Int, bound: Int): List<Int> {
        val iBound = if (x == 1) 1 else (log10(bound.toDouble()) / log10(x.toDouble())).toInt()
        val jBound = if (y == 1) 1 else (log10(bound.toDouble()) / log10(y.toDouble())).toInt()
        val set: HashSet<Int> = HashSet()
        for (i in 0..iBound) {
            for (j in 0..jBound) {
                val number = (x.toDouble().pow(i.toDouble()) + y.toDouble().pow(j.toDouble())).toInt()
                if (number <= bound) {
                    set.add(number)
                }
            }
        }
        return ArrayList(set)
    }
}

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