class Solution {
public:
int maximumNumberOfStringPairs(vector<string>& words) {
int n = words.size();
int res = 0;
for (int i = 0; i < n; i ++ ) {
string t = words[i];
reverse(t.begin(), t.end());
for (int j = 0; j < n; j ++ ) {
if (i != j && words[j] == t)
res ++ ;
}
}
return res / 2;
}
};