1.6 KiB
1.6 KiB
Leetcode Single-Number
2022-07-22 15:31
Algorithms:
#algorithm #bit_manipulation
Data structures:
#DS #bitset
Difficulty:
#coding_problem #difficulty-easy
Additional tags:
#leetcode
Revisions:
N/A
Related topics:
tag:#bit_manipulation
Links:
Problem
Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.
You must implement a solution with a linear runtime complexity and use only constant extra space.
Examples
Example 1:
Input: nums = [2,2,1] Output: 1
Example 2:
Input: nums = [4,1,2,1,2] Output: 4
Example 3:
Input: nums = [1] Output: 1
Constraints
1 <= nums.length <= 3 * 104-3 * 104 <= nums[i] <= 3 * 104- Each element in the array appears twice except for one element which appears only once.
Thoughts
[!summary] This is a #bit_manipulation problem utilizing the XOR operator
The XOR operator has some properties:
a ^ a = 0;
a ^ b ^ a = a ^ a ^ b = b;
This can be used for our problem.
Solution
class Solution {
public:
int singleNumber(vector<int> &nums) {
// Using XOR operator
int ans = 0;
for (int i : nums) {
ans ^= i;
}
return ans;
}
};