leetcode982 Triples with Bitwise AND Equal To Zero

思路：

使用unordered_map暴力枚举。

实现：

 #include <bits/stdc++.h>
 using namespace std;
 class Solution
 {
 public:
     int countTriplets(vector<int>& A)
     {
         unordered_map<int, int> mp;
         int n = A.size();
         for (int i = ; i < n; i++)
         {
             for (int j = ; j < n; j++)
             {
                 int tmp = A[i] & A[j];
                 if (!mp.count(tmp)) mp[tmp] = ;
                 mp[tmp]++;
             }
         }
         int ans = ;
         for (int i = ; i < n; i++)
         {
             for (auto it: mp)
                 if ((A[i] & it.first) == ) ans += it.second;

         }
         return ans;
     }
 };
 int main()
 {
     int a[] = {, , };
     vector<int> v(begin(a), end(a));
     cout << Solution().countTriplets(v) << endl;
     return ;
 }