leetcode@ [136/137] Single Number & Single Number II

https://leetcode.com/problems/single-number/

Given an array of integers, every element appears twice except for one. Find that single one.

Note:
Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

class Solution {
public:
int singleNumber(vector<int>& nums) {
if(nums.size() == 1) return nums[0];

vector<int> bitNums(32, 0);

int res = 0;
for(int i=0;i<32;++i) {
for(int j=0;j<nums.size();++j) {
bitNums[i] += (nums[j] >> i) & 1;
cout << ((nums[j] >> i) & 1) << " ";
}
cout<<endl;
}

for(int i=0;i<bitNums.size();++i) {
res += (bitNums[i] % 3) << i;
}
return res;
}
};

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