Python Collections & itertools
IntermediateStop reinventing wheels. Counter, heapq, and itertools solve real production problems in a single line.
Foundations
01
Top K Frequent (Counter)
Medium10m
02
Merge K Sorted (heapq)
Hard20m
Group By Key (defaultdict)
Easy8m
04
Sliding Window Max (deque)
Hard20m
05
Combinations & Products
Medium12m
Core
06
Chain & Flatten
Medium10m
07
Ordered Window (OrderedDict)
Medium15m
08
Bisect Insert Patterns
Medium12m
09
Priority Queue with heapq
Medium12m