single-number-ii

class Solution {
public:
int singleNumberII(vector<int> &A) {
int n=A.size();
vector<int>count(32,0);
int res=0;
for(int i=0;i<32;i++){
for(int j=0;j<n;j++){
if((A[j]>>i)&1) count[i]++;
}
res|=(count[i]%3)<<i;
}
return res;
}
};