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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0901_1000.s0970_powerful_integers;

// #Medium #Hash_Table #Math #2022_03_31_Time_1_ms_(100.00%)_Space_42.3_MB_(27.54%)

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

/**
 * 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 + y^j 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
**/
public class Solution {
    public List powerfulIntegers(int x, int y, int bound) {
        int iBound = (x == 1 ? 1 : (int) (Math.log10(bound) / Math.log10(x)));
        int jBound = (y == 1 ? 1 : (int) (Math.log10(bound) / Math.log10(y)));
        HashSet set = new HashSet<>();
        for (int i = 0; i <= iBound; i++) {
            for (int j = 0; j <= jBound; j++) {
                int number = (int) (Math.pow(x, i) + Math.pow(y, j));
                if (number <= bound) {
                    set.add(number);
                }
            }
        }
        return new ArrayList<>(set);
    }
}