Leetcode 970. Powerful Integers

Gary Chiang
1 min readApr 30, 2021

--

[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

[Test Points]

  1. No duplicate — need to use set as datastructure.
  2. have to change set into List<Integer>
  3. how to handle corner case — when x or y equals to 1

[Notes]

  1. reate situable data structure, in this case, hashset and arraylist
  2. for loops using i *= x, get the power of x
  3. corner case need to be careful

[Ans-@wangzi6147]

[Second- @416486188]

--

--

Gary Chiang
Gary Chiang

Written by Gary Chiang

CS new grad, 6 years experience related to supply chain management. Located in Bay area

No responses yet