Problem
Given an integer num, return three consecutive integers (as a sorted array)** that sum to num. If num cannot be expressed as the sum of three consecutive integers, return an empty array.**
Example 1:
Input: num = 33
Output: [10,11,12]
Explanation: 33 can be expressed as 10 + 11 + 12 = 33.
10, 11, 12 are 3 consecutive integers, so we return [10, 11, 12].
Example 2:
Input: num = 4
Output: []
Explanation: There is no way to express 4 as the sum of 3 consecutive integers.
Constraints:
0 <= num <= 1015
Solution (Java)
class Solution {
public long[] sumOfThree(long num) {
if (num % 3 == 0) {
return new long[] {num / 3 - 1, num / 3, num / 3 + 1};
}
return new long[0];
}
}
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).