C++ Short, O(N^2) Time O(N) Space, 173ms Beats 90%, Using HashMap

[moytrage]

class Solution {
public:
    inline int sqr(int x) { return x * x; }
    inline int d(pair<int, int> const & p1, pair<int, int> const & p2) {
        return sqr(p1.first - p2.first) + sqr(p1.second - p2.second);
    }
    int numberOfBoomerangs(vector<pair<int, int>>& ps) {
        int result = 0;
        unordered_map<int, int> cnts(ps.size());
        for (auto& i: ps) {
            cnts.clear();
            for (auto& j: ps) ++cnts[d(i, j)];
            for (auto& c: cnts) result += c.second * (c.second - 1);
        }
        return result;
    }
};