Single Number Problem & Solution
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.
See the single number problem on LeetCode.
C++ Solution
#pragma GCC optimize("Ofast")
#pragma GCC optimization("unroll-loops")
static const int _=[](){std::ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();
class Solution {
public:
int singleNumber(vector<int>& nums) {
int result = 0;
for (int i = 0; i < nums.size(); ++i) {
// Performs a XOR to cancel out numbers that repeat again.
result ^= nums[i];
}
return result;
}
};