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# 970. Powerful Integers

2周前 (04-30) 8次浏览

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`
```class Solution {
public List<Integer> powerfulIntegers(int x, int y, int bound) {
Set<Integer> set = new HashSet();
int a = 1;
while(a < bound) {
int b = 1;
while(b < bound) {
if(a + b <= bound) set.add(a + b);
if(y == 1) break;
b *= y;
}
if(x == 1) break;
a *= x;
}
return new ArrayList(set);
}
}```

a = a*x，b = b*y。a、b都从1开始。