STL is a very powefull tool for competitive programming. It saves a lot of time and makes your code easier to read.
Click in the links to see the notes on that topic
- String
- Pair
- Vector
- Iterator
- Stack
- Queue
- Deque
- Priority Queue
- Set
- Multiset
- Unordered Set
- Unordered Multiset
- Map
- Multimap
- Unordered Map
- Unordered Multimap
- List
Also some useful features like `next_permutaion() , stringstream` etc in this **link**