1 class Solution { 2 public: 3     int singleNumber(int A[], int n) { 4         int a[32] = {0}; 5         int i = 0; 6         while(i < n) 7         { 8             int j = 0; 9             int num = A[i];10             while(j < 32)11             {12                 a[j] += num&1;13                 num = num>>1;14                 ++j;15             }16             ++i;17         }18         i = 0;19         int ans = 0;20         while(i < 32)21         {22             if(a[i]%3 != 0)23             {24                 ans = ans|(1<<i);25             }26             ++i;27         }28         return ans;29     }30 };