best and fast code
IntuitionApproachComplexity
Time complexity:

Space complexity:
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity:
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity:
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```java []
class Solution {
    public int maximumNumberOfStringPairs(String[] words) {
        HashSet<String> set=new HashSet<>();
        int count=0;
        for(int i=0;i<words.length;i++){
            String rev=reverse(words[i]);
            if(set.contains(rev)){
            count++;
            set.remove(rev);}
            else
            set.add(words[i]);
        }
        return count;
    }
    public String reverse(String s){
        StringBuilder sb=new StringBuilder(s);
        sb.reverse();
        return sb.toString();
    }
}
```
['Array', 'Hash Table', 'String', 'Simulation', 'Java']