LeetCode-in-Go
137. Single Number II
Medium
Given an integer array nums where every element appears three times except for one, which appears exactly once. Find the single element and return it.
You must implement a solution with a linear runtime complexity and use only constant extra space.
Example 1:
Input: nums = [2,2,3,2]
Output: 3
Example 2:
Input: nums = [0,1,0,1,0,1,99]
Output: 99
Constraints:
1 <= nums.length <= 3 * 104-231 <= nums[i] <= 231 - 1- Each element in
numsappears exactly three times except for one element which appears once.
Solution
func singleNumber(nums []int) int {
ones := 0
twos := 0
for _, num := range nums {
ones = (ones ^ num) & (^twos)
twos = (twos ^ num) & (^ones)
}
return ones
}