Clean 4 line c++ o(n) solution


#1
int Solution::diffPossible(const vector<int> &A, int B) {
    unordered_map<int,int> m;
    for(auto x : A)
    {
        if(m.find(x+B) != m.end()  || m.find(x-B) !=m.end() )
            return 1;
        m[x] ++;
    }
    return 0;
}